On the eve of his wedding to Rita -- and Connor leaving for the Witness Protection Program -- Pride must track down who attacked Jimmy and Connor, while he navigates Sasha's ulterior motives regarding her son.

A car crash results in the death of a photographer; Maggie sympathizes with his widow when she notices similarities with her own husband's death.

After an altercation with a student, teacher Patrick Miller goes missing, leading the team to investigate everyone who might have had a grudge against him; a key witness in the case steps up to help.

A former kidnapping victim is linked to a series of murders that includes the daughter of an NYPD detective; Kristen begins to doubt her ability as an agent after a training exercise leaves her shaken.

After a businessman with a history of harassment claims against him is killed, the team suspects the killer may be one of his many accusers.

A bank holdup leads the team to a safe deposit box, the contents of which have the potential to destroy national security; Kristen is eager to get back into field work while other team members still have their concerns.

The son of a retired FBI agent is kidnapped, and the team must investigate if it's an act of revenge; Isobel must make a hard call when information from the past comes to light.

A nefarious virus is uploaded to Walter's computer, turning the team's new "smart" building project into a death trap with people locked inside.

A nefarious virus is uploaded to Walter's computer, turning the team's new "smart" building project into a death trap with people locked inside.

The team must intervene when Paige and Ralph are on a sabotaged, runaway subway train; Toby tries to impress Happy during his first boxing match.

The members of Team Scorpion take a lucrative job locating a top-secret aircraft in Area 51 for the CIA.

Team Scorpion is blackmailed into breaking into the United Nations to help with the assassination of an arms dealer; Sylvester tries to protect Megan's wishes.

When the team and Walter's parents visit Megan in the hospital, a deadly fungus outbreak occurs, forcing everyone into quarantine.

The members of the BAU team track an unknown subject who appears to be fascinated with medical experimentation.

Reid plays a central role in the BAU's elaborate plan to take down a ring of hit men known as the Dirty Dozen.

When corpses are discovered in public places in Boston, a ride-sharing service may lead the team to the killer.

The BAU looks for a suspect and a motive when victims are found in truck stop restrooms in the South.

An 18-year-old woman escapes from the home where she and two other women were held captive for years.

The BAU team combs Los Angeles for a suspect after security footage is discovered, which shows an unknown subject being invited into victims' homes.

When Morgan is abducted, the members of the BAU team race against time to find him and save his life.

The team searches for an unknown subject who takes children while their parents are asleep; Morgan tries to find out who attacked him.

The team investigates the death of a petty officer whom Pride had mentored; Brody searches for a place to call home.

When a Navy lieutenant on liberty dies of bubonic plague, NCIS Special Agent Tony DiNozzo helps the New Orleans team as they try to control a potential outbreak and find the source of the infectious disease.

An armored transport bus crashes, resulting in the escape of four prisoners -- including a black market broker topping the list of national security threats; Pride needs Gibbs' help with a case file full of redactions.

When a Navy SEAL is found dead in a sorority house, the team must determine if his death was related to collegiate foul play or a classified mission; Pride's daughter visits the office.

When an attorney is found dead near the body of a private escort, the team must piece together what connected the two seemingly random victims; Jubal's connection with one of the victims makes finding the killer much more personal.

After a truck filled with armor-piercing rifles is hijacked, the team works to discover who stole it, and what they have planned for the stolen weapons; a friend from OA's past returns to help with the case, but OA isn't sure he can trust him.

After the police ignore a desperate father's plea for help, he abducts a billionaire's daughter and holds her hostage in a safe room until his own missing child is returned to him; Jubal puts his hostage negotiation skills to the test.

When the team is called to the scene of a murder, it quickly suspects political motivation; Maggie contemplates a decision that could affect her entire career.

Jess LaCroix and his team come to help OA find a fugitive LaCroix arrested years ago after a bus with 26 students goes missing, and he's the main suspect.

The team investigates a drug deal gone bad after the body of a college student is found; Detective Hailey Upton temporarily joins the team and finds her investigative methods clash with the Bureau's more buttoned-up environment.

The members of the team go under cover at a university in order to track a hacker who is putting the world economy at risk.

Team Scorpion must stop a catastrophe on Christmas Eve when heavy rain creates a large crack in a dam, putting an entire town in danger.

The members of Team Scorpion brave subzero temperatures in Antarctica to save a United States Special Forces unit; Toby risks his life to save Happy.

Sylvester's father, a retired general, asks the team for help when he thinks a dictator in Africa has uncovered weapons of mass destruction from World War II.

The members of Team Scorpion are asked to help NASA with a top-secret rocket launch, but they must sabotage their own mission when Walter's date finds a bomb strapped to her chest.

When a powerful earthquake hits Los Angeles, Team Scorpion must prevent a pinched gas line from causing a massive explosion.

When an unsub targets the BAU, the team pursues the person who is responsible for the actions.

Emily looks to the BAU for help when tracking an international serial killer; the BAU deals with Morgan's departure.

The BAU hunts for an UnSUB who deliberately disfigures victims; Rossi and his ex-wife have an uncomfortable reunion.

The BAU plays a dangerous cat and mouse game with a convicted serial killer who may have information on the whereabouts of two kidnapped boys.

Hotch is arrested by a SWAT team and suspected of conspiracy; when the team members scramble to prove Hotch's innocence, they discover a larger plot may be on the horizon.

New recruit Luke Alvez helps the team capture a killer who escaped from prison with 12 other convicts.

J.J. is shaken after investigating the case of two abducted children, and tells her husband about the events.

As the BAU welcomes back Emily Prentiss, they're called upon to investigate the disappearance of three women.

The investigation into a chief warrant officer's death reveals that his wife has been abducted -- leaving the team with a 22-hour deadline; senior FBI agent Fornell assists with the case.

Amidst Halloween festivities in New Orleans, a Naval Staff Judge Advocate dressed in a costume is found dead in a cemetery; the team debates Halloween costumes and activities.

The team investigate the murder of a Navy Officer assigned as a tech liaison with a private developer; Pride turns the carport into an auto shop.

A murdered petty officer -- with a proposal and an engagement ring -- is found in a Mardi Gras float storage facility; the members of the team are baffled when they cannot locate the victim's girlfriend.

The team welcomes a new member, Special Agent Tiffany Wallace, as they search for killers who orchestrated a mass shooting at a media company; OA's personal connection with the case threatens to cloud his judgment.

The team races to stop an active serial killer after three women are found weighted down at the bottom of a lake; Jubal looks into an old closed case after there are multiple similarities to the recent victims.

When the leader of a drug cartel and one of the world's most wanted men is apprehended by the team, the entire FBI headquarters is put at risk when his henchmen unveil a plot to free him; Isobel must make a difficult decision.

A shooting at a quinceañera leaves two dead, but the team believes they may not have been the intended targets; Maggie is conflicted as the team decides the best plan of action for using a witness to take down their suspect.

The team searches for a young girl who was kidnapped from a cabin during a family vacation; Maggie questions her relationship with Nestor when she learns he hasn't been completely honest with her.

The team must infiltrate a drug trafficking gang after the robbery of a chemical plant leaves two customs agents dead; Nestor offers his help on the case, giving Maggie new insight into his character.

The smoldering corpse of an Asian girl is found outside the Chinese consul general's apartment, and detectives suspect she immolated herself as a political statement.

Detectives suspect foul play when a teenager dies after being struck by a vehicle in front of a coffee shop.

When half of a two-man gambling operation is found murdered, the detectives finger his partner as the prime suspect.

A vigilante priest kills a notorious drug dealer in the name of God; Briscoe is reminded of his daughter's death at the hands of a trafficker.

Two seemingly unrelated murders, stolen jewels and a case of mistaken identity lead to a defendant being tried for a crime without being present at the trial. Mandy Patinkin and Andrew McCarthy guest star.

When a car salesman is found bludgeoned to death, Detectives Briscoe and Green search for his last customer.

A cosmetics tycoon (Lucie Arnaz) is involved in controversial stock transactions, scandalous affairs and hormone-replacement therapy.

A media-savvy attorney (Gregory Hines) defends a black teenager accused of shooting an off-duty police officer.

Detectives investigating a cabdriver's death discover his last fare was a gifted writer with a violent streak.

After a woman's body turns up in the East River, the detectives discover she recently had attended a professional football player's birthday party.

The lead suspect in the murder of a Manhattan executive claims his knowledge of the crime came from a psychic vision.

Investigators identify multiple suspects in the murder of the admissions director at an ultra-elite private school, including its headmaster (guest star Roger Rees).

The corpse of a Russian model shows many old injuries, convincing the detectives that she had been the victim of abuse.

A sniper shoots four people at random in Manhattan and causes a citywide panic; Jack and Serena uncover a shocking truth behind the shootings.

The team reopens a cold case when a stolen Navy-issue gun turns out to belong to a chief petty officer who died 40 years ago; the team makes their annual Thanksgiving dinner together.

A retired SEAL -- who tracked people impersonating military personnel -- is murdered; Brody finds that LaSalle is uncharacteristically unenthusiastic about Christmas.

The investigation into an explosion at the Navy-Marine Corp Relief Gala reveals Pride was the bomb's target.

The NCIS team and the Coast Guard Investigative Service work together when a Navy Admiral's daughter is the prime suspect in a double murder on a research boat; Lasalle looks for his estranged brother.

McGee and his wife Delilah's Bahamian vacation turns into a high-stakes mission; Gibbs fears the worst when his search for Fornell leads to blood.

Following a tip about smuggled weapons, Bishop and Torres engage in a shootout in a former sheriff's residence that's now a historical site, only to find themselves locked in abandoned jail cells there.

NCIS investigates the murder of a Navy officer who was killed while driving home a recently released inmate; Gibbs helps Palmer deal with a personal trauma.

When Sloane's name is discovered in Afghanistan at the site of an abandoned bus with a dead driver, Gibbs accompanies her on a trip to find a group of girls who were kidnapped from the bus; a hacker emails compromising information to the Taliban.

NCIS dives into the competitive world of food trucks after finding a man frozen to death in the back of one.

The team uncovers a secret dogfighting ring, which leads to an unexpected move by one of the team members.

Gibbs and Fornell's crusade to find the head of the drug ring responsible for Fornell's daughter Emily's overdose comes to a climax; Gibbs and Vance finally let the team in on a case that has dangerous implications.

Vance assigns McGee, Torres and Bishop to COVID compliance duty at a foreign affairs summit, where they discover a link to another NCIS team's murder case.

The team hunts a killer who is fatally shooting seemingly unrelated targets; new agent Tiffany Wallace experiences tension between her work as an FBI agent and the responsibility she feels to her community as a Black woman.

After a bomb leaves three people dead, the team presses a reluctant informant to gather information from his close friends who are under suspicion; OA and his girlfriend clash over where the informant's rights lie.

When a reporter is kidnapped and held without a ransom demand, the team must dig into her past relationships in order to pin down her assailant's motive; Isobel's relationship comes under fire when the case makes a connection to her boyfriend.

Alex Browning is embarking on a trip to Paris. He experiences a premonition -- he sees the plane explode moments after leaving the ground. Insisting that everyone get off the plane, Alex and seven other people are forced to disembark. All watch as the plane actually explodes in a fireball. He and the other survivors have briefly cheated death, but will not be able to evade their fate for very long. One by one, these fugitives from fate fall victim to the grim reaper.

Kimberly (A.J. Cook) has a premonition of a horrible highway accident killing multiple people -- including her and her friends. She blocks the cars behind her on the ramp from joining traffic -- and as a police trooper (Michael Landes) arrives, the accident actually happens. Now, Death is stalking this group of mistaken survivors -- and one by one they are dying as they were supposed to on the highway.

Six years after a group of high-school students first cheated death, another teen (Mary Elizabeth Winstead) has a premonition that she and her friends will be involved in a horrifying roller-coaster accident. When the vision proves true, the student and her fellow survivors must deal with the repercussions of cheating the Grim Reaper.

Alex Browning is embarking on a trip to Paris. He experiences a premonition -- he sees the plane explode moments after leaving the ground. Insisting that everyone get off the plane, Alex and seven other people are forced to disembark. All watch as the plane actually explodes in a fireball. He and the other survivors have briefly cheated death, but will not be able to evade their fate for very long. One by one, these fugitives from fate fall victim to the grim reaper.

After learning he was poisoned with a deadly dose of radiation, a Navy lieutenant commander asks Pride and the team to solve his imminent murder.

An agent is killed while working on a security detail for the Vice Chief of Naval Operations; Brody's past is evaluated.

A petty officer is murdered during Mardi Gras festivities; Pride contemplates what to tell his daughter about his strained relationship with his father.

The NCIS team tries to narrow down the motive when a Navy recruiter is murdered in a hit-and-run; Lasalle worries about his brother.

Pride believes Baitfish has returned and has the NCIS team chase down leads in an attempt to locate him.

When a sailor is killed in a strip club, the murder weapon turns out to be linked to other unsolved cases; Brody receives a visit from her ex-fiance.

Evidence from the stabbing of a Marine sergeant leads Torres to meet his father, who left when Torres was a child.

The team investigates a biker killed in a hit-and-run; Gibbs prepares to testify against a financial adviser who stole millions from his Navy clients.

NCIS tracks a stolen laptop to the uncle of a young boy, Phineas, Gibbs' former neighbor.

When members of an NCIS Regional Enforcement Action Capabilities Training Team are killed during an explosion, NCIS Special Agent Jessica Knight, the lone surviving member, helps crack the case using high-tech body armor.

While pursuing a dangerous arms dealer, the team is shocked when Bishop is implicated in an old NSA leak; Gibbs and Marcie realize the killer they've been tracking may be onto them.

As the NCIS team searches for Gibbs after wreckage from his boat is discovered; they find out he was tracking a serial killer with journalist Marcie Warren, who wrote an exposé on him.

While trying to find the serial killer Gibbs was after, the NCIS team discovers another person has been tracking the case as well.

Gibbs and Parker go on a road trip to find one of the serial killer's victims; Agent Knight goes under cover at a large manufacturing company with ties to the murders.

Gibbs and McGee head to Alaska while the team works at home to uncover the conspiracy behind the serial killer.

The NCIS team investigates the death of a Navy commander whose body suddenly explodes before Jimmy can examine it.

NCIS investigates the death of a beloved Navy commander who trained some of the top athletes in the country.

NCIS investigates the death of a man on a cruise ship whose body is discovered in the ship's sauna by McGee's mother-in-law.

The team searches for a serial killer along the Appalachian Trail in rural Virginia.

The BAU investigates the case of two murdered families, where two high school students are the sole survivors.

Three children vanish while riding their bikes on the same path where a similar unsolved disappearance took place 30 years earlier.

A man who believes himself to be the brother of Dr. Tara Lewis arrives in town, knowing everything about Tara's family; Tara is unable to make contact with her real brother.

The BAU team investigates when the remains of a dozen people are discovered along a creek bed in Yakima, Wash.

While conducting a profiling course on his birthday, Rossi gets a call from serial killer Tommy Yates, who gives him the location of his latest victim.

The team investigates when home invasions involving casualties strike upscale neighborhoods in San Diego.

The BAU investigates when a bizarre hieroglyph is found under a deceased homeless man's armpit; Reid decides to take his mother out of a clinical study early to bring her home.

During the autopsy of a petty officer who seems to have died of natural causes, an armed man holds Wade, Sebastian and Danny hostage in the morgue.

When a Navy commander's car is stolen with his baby inside, the team must determine if it was a targeted abduction.

LaSalle's brother, Cade, needs the team's help when he becomes a murder suspect -- and cannot remember what happened; LaSalle is determined to prove Cade's innocence, despite the wealth of evidence against him.

Baitfish murders a person close to the team in order to send a message to Pride; a citywide hunt for the elusive criminal takes place.

Pride has suspicions about a mole; new intelligence comes to light that indicates a breach at the ports.

Pride and the team must go on a dangerous undercover mission to retrieve a stolen missile and prevent an attack.

A blogger dedicated to exposing government corruption is murdered; during the investigation, it is revealed that a war crime may have occurred during a humanitarian effort in Bolivia.

A comic's infant son dies after being dropped from a high-rise window, leading detectives to a dark secret.

The detectives follow a string of mysterious homicides; a woman runs over her unfaithful husband; a murdered woman has an uncertain relationship to her brothers.

The detectives stumble upon a serial killer while investigating the rape and murder of a teenage girl.

A bounty hunter turns up dead while trailing a fugitive rapist and bookstore heir.

A carjacking involving SARS forces detectives to search for the initial patient infected to prevent an outbreak.

Detectives link the murder of an actress to a member of her therapy group, then focus their attention on a Tony-winning songwriter.

Detectives investigate a fire that ripped through a 300-plus audience at a rock concert, killing 23 fans.

An unemployed executive deposits $400,000 in his savings account before being gunned down in his upscale brownstone.

The detectives attempt to identify a body that was found floating in the Hudson River; after the victim is identified, her husband becomes the prime suspect.

A war correspondent who reputedly endangered U.S. troops in Iraq gets shot in the back with a military-issue handgun.

Detectives investigate the poisoning death of a grief counselor who claimed to communicate with the dead in order to comfort clients.

When the owner of a clothing company is beaten to death in his office, Briscoe and Green believe the prime suspect entered the factory just before the murder.

Prosecutors go after a driver who struck a homeless man, went home with the victim trapped in her windshield and let him die in her garage.

Detectives investigate the murder of a mob informant who sent a kingpin to jail.

A motivational speaker is pushed off a hotel balcony, then her daughter is abducted.

Detectives uncover an extensive list of suspects after a gunman storms City Hall, killing a councilman and a water inspector.

Detectives investigate the strangling of a peace activist who had a very confrontational approach.

The team must track down two assailants who wear animal masks while committing armed robberies; Tiffany and Scola butt heads on whether to accept the local NYPD's offer to help in the investigation.

After a man is killed by an explosive package shipped to his home, the team attempts to capture the sender and intercept his latest deadly parcel; Maggie struggles to trust her younger sister.

The team rushes to track down two doctors abducted by a desperate father willing to do anything to save his son; Jubal's uncertainty in his family life affects his judgement during the hostage situation.

When the CEO of a major brokerage firm is killed while surrounded by protesters, the team looks into who had the most to lose from his company's perceived manipulations; Scola's previous Wall Street career and the reasons he left come to light.

While investigating a mass casualty incident at a New York City restaurant, the team scrambles to determine if it was racially motivated and if there was more than one gunman; Maggie starts to notice troubling behavior from her co-worker Elise.

When five prominent men are gunned down at a trendy New York restaurant, the team's investigation brings them into contact with a lieutenant in Antonio Vargas' cartel, triggering a showdown between Isobel and Vargas.

After a young woman is killed on her way home from a lavish yacht party, the team investigates who she was and how she came to be at the event.

Team Scorpion must stop an influx of drugs that are being smuggled into the country via drones; an ultimatum is issued.

Sylvester wins big on "The Price Is Right"; the team must infiltrate a high-end car smuggling operation that is preparing to ship weapons to South America.

The team investigates after the Los Angeles blood supply is hacked and tainted, which leaves a young girl who is in need of a heart transplant in peril.

The team must save Cabe when he is captured during a secret mission in Djibouti, Africa, with his protege, Tim Armstrong (Scott Porter).

A deadly tornado threatens the lives of Team Scorpion during a mission to recover the remains of fallen Marines in Vietnam.

The team is hired by the Department of Defense to test the security at Fort Knox by trying to break in and steal a precious artifact.

The BAU team is called in to investigate when male bodies are discovered that seem to be impossible to identify.

When a BAU member gets in trouble in Mexico, the team enlists the services of the International Response Team for help.

The BAU looks into the cause of several fatal car crashes involving drivers and pedestrians; Reid gets bad news.

The BAU investigates a series of disfiguring acid attacks on young men and women; Dr. Reid begins to settle into his new surroundings.

A mother steps forward with valuable information for the BAU to aid in their investigation of an unsub known as the bone crusher; Reid must adapt to a new set of rules in prison.

The BAU believes two unsubs may be operating simultaneously when victims killed in two different ways are discovered in the same city; the team grapples with keeping Reid safe in prison.

The BAU investigates an urban vampire who kidnaps his victims at night and holds them underground in the sewer system; Reid makes a difficult decision in prison.

The BAU is called to investigate after three victims are discovered tied to stakes in the brutal Arizona desert.

When a highly regarded Navy pilot is killed after crashing a new, high-tech jet at an air show, the team must determine if it was human or mechanical error.

The NCIS team investigates when a Navy drone pilot is murdered after using a black market drone to obtain military surveillance.

When an Australian Royal Navy Lieutenant is murdered in New Orleans, Special Agent Naomi Parsons (Kate Beahan) is sent to work with Special Agent Pride.

When a petty officer is found dead, the team's participation in the annual Red Dress Run comes to a halt.

Maggie, OA and the team must stop a hacker who is disabling life-saving equipment in several New York City hospitals; Jubal's son waits for important surgery at one of the impacted hospitals.

The team finds a connection between bombings and a private veterans' club in New York City; Isobel tells a reluctant OA to recruit a former Army buddy for intel.

The team hunts for a serial killer who is targeting young, homeless men; Tiffany and Scola don't see eye to eye on how to handle the case.

After a suburban woman is kidnapped from her home, the team looks into trysts on both sides of a seemingly perfect marriage; OA feels pressure from Mona to make changes in his career path.

The team must track down a shooter targeting detectives from the same precinct and unit while facing mounting tension from the NYPD; Tiffany finds that her NYPD roots may be influencing her view of the situation.

After a young girl is kidnapped from her daycare, the team must help her parents navigate a debt owed to the deadly gang in their neighborhood; Maggie struggles to focus on the case when her sister returns from rehab.

In Chernobyl, Sylvester and Paige become trapped inside a decaying nuclear reactor that the team is trying to repair before a tragic meltdown.

The team must outsmart mentally unstable ex-Scorpion member Mark Collins when he kidnaps Toby and threatens to kill him if his demands are not met.

The team members set aside their personal and romantic issues when hackers take over targeted U.S. military aircraft and war ships, pointing the weaponry at American cities.

The team members set aside their personal and romantic issues when hackers take over targeted U.S. military aircraft and war ships, pointing the weaponry at American cities.

When Walter is accidentally launched into space in a rocket, Team Scorpion must find a way to bring him home before his oxygen runs out.

A boy from Ralph's class goes missing after having a run-in with a deadly criminal; Toby comes closer to discovering the identity of Happy's husband.

The BAU investigates when several federal government employees, including a close friend of Walker's, succumb to symptoms of a heart attack; Reid anxiously awaits his trial date.

When Reid fears his mother has been abducted, he asks the BAU to investigate while he's stuck in prison.

Morgan brings the BAU new information in the case against Mr. Scratch, a serial killer and escaped convict who has been wreaking havoc on the team.

Agent Matt Simmons joins the BAU team in a race to take down Mr. Scratch and save one of their own in the process.

The BAU investigates three similar crimes in which victims' remains are discovered in old suitcases.

The BAU investigates a workplace shooting committed by a state-of-the-art drone in Silicon Valley.

When an anger-driven, unknown subject targets successful businessmen in Detroit, the BAU must investigate.

The BAU must find out what several missing women have in common to find them.

An extremely intelligent Navy coder -- employed by Brody's mom (Annie Potts) -- is put in danger when the heart intended for him is stolen.

After traveling to Texas to escort a key witness to the trial of an infamous arms dealer, Sonja and Special Agent Pride are ambushed.

During a blackout in New Orleans, Pride is determined to figure out who murdered a family friend's fiancé.

A Marine's murder reveals new clues in the first case LaSalle and Pride worked together; a Thanksgiving celebration at Pride's bar.

A widow is shocked that her new "boyfriend" is the manipulative leader of a terrorist group planning an attack; Scola is reminded of his brother's death on 9/11; Tiffany worries about his emotional choices during the investigation.

After Rina is critically wounded while heading to work with Jubal; the team makes the chilling discovery that a vengeful Vargas orchestrated the shooting from behind bars and continues to target the rest of their team and their loved ones.

As the team investigates a string of jewelry store robberies that culminate in a double murder, they uncover a connection to a 16-year-old boy trying to survive the foster care system.

The team searches for an abducted college coed; Jubal has a tense encounter with Rina's mother.

Maggie goes undercover working in a bar to investigate an anti-government group that regularly gathers there; a single father on the periphery of the group begins to fear he's in danger of becoming collateral damage.

When a Muslim college student and his younger brother are murdered, the team connects with the outraged imam of OA's former mosque, who insists the victims were wrongly targeted as terrorists.

A simple job at the Los Angeles Natural History Museum turns deadly when thieves steal things from a rare gem exhibit to get the materials they need to make a nuclear bomb.

Team Scorpion explores a deep cave system in an effort to prevent a bat population from harming the North American ecosystem; the team dons Halloween costumes for Walter's impending immigration inspection.

On election day, someone tries to create turmoil in the U.S. presidential election, and Team Scorpion is called to investigate.

While in Ireland for Megan's one-year memorial, Walter discovers a natural disaster at a nearby lake has created a poisonous cloud that threatens an entire village; Cabe and Toby try to ease the tension between Tim and Walter.

When Paige's estranged mother stumbles upon a forgotten nuclear reactor precariously close to exploding, she calls on the team for help.

Walter takes a perilous swim to rescue a woman trapped in the La Brea tar pits; Paige's mother maximizes Ralph's troop cookie sales.

Morgan returns to the BAU to help Penelope deal with a case that has affected her emotionally.

The BAU searches for a subject who is targeting prominent members of the community.

The BAU is called in to investigate when a criminal sensationalizes his crimes by giving the local media exclusive footage.

The BAU is called to investigate when two members of a conspiracy group in Roswell, N.M., perish in quick succession.

When a series of backyard pool homicides are reported in California, the BAU team searches for an UnSub which has a puzzling past.

The BAU team's investigation into the home invasion and attempted homicide of a police chief's wife uncovers a world of secrets in a small town in Virginia.

The BAU is called to New York when several casualties of a brutal nature are reported in Central Park.

The BAU is called to investigate a series of homicides in which cryptic messages are found inside the mouths of the victims.

Wade's adopted son becomes a suspect after a series of Christmas burglaries turn deadly; Brody and LaSalle tease Sonja about the team's holiday gift exchange.

Special Agent Pride and the team investigate a Russian sleeper agent involved with Abby's brother; Sebastian goes to Washington, D.C., to work with Abby; Bishop drives all night to deliver a package and help the New Orleans team.

The staged suicide of a petty officer turns out to be murder; the team secretly works on an online dating profile for Pride.

A Mardi Gras celebration at Pride's bar is cut short when he and Mayor Douglas Hamilton (Steven Weber) are abducted by unknown assailants.

The team investigates an extremist gun group after an anti-gun lobbyist building is bombed; SAC Bashar dangles a possible promotion for OA.

The team realize they have a cross-country serial killer on their hands; the case has ties to Isobel's father, Robert, and his hotel, leading to revelations about their fractured relationship.

After an immigration agent is fatally shot at a hockey game, the team attempts to find the shooter, who they believe may also be targeting Congressman Curtis Grange, who was at the same game.

When a young couple is found murdered in a New York City park after returning from a vacation, the team searches for a suspect linked to the drug trade; Scola turns over a new leaf when it comes to his relationships.

OA is forced to confront one of his biggest fears when the team discovers that deadly sarin gas may have been sold to terrorists.

When a morning show host is murdered inside her home, the team tracks the killer; things become awkward for Scola when agent Nina Chase becomes part of the team during Maggie's recovery.

A woman witnesses the shooting of a low-level drug dealer, then she is murdered before she can identify the killers.

Briscoe and Green search for a killer and a motive when parts of an East Village resident's body are discovered in different trash piles.

After an elderly woman is found beaten to death in her apartment, detectives discover she was the lead witness in the deportation prosecution of a reputed Nazi war criminal.

Jack McCoy learns that his old colleague, ADA Daniel Tenofsky, has been murdered, and detectives discover he was living and working under a false identity.

Detectives investigate a slain Hollywood producer's involvement with a mob movie to find a motive for his murder.

When New York's most infamous baseball fan is stabbed to death in a bar, detectives suspect the killer is probably a sports aficionado.

A female Japanese tourist is shot to death, prompting an investigation that leads the police to the victim's husband.

The detectives believe a bride, motivated by greed, killed her groom after the wedding, until they find the murder weapon in her daughter's room.

When a deliveryman is gunned down on his route, Briscoe and Green discover that he was active on a Web site for arranged liaisons and that his wife had just bought a gun.

Terms of the Geneva Convention come into play when the sister of a former inmate at Abu Ghraib prison is suspected of murdering a female Guardsman in the second Gulf War.

The ex-wife of a firefighter who married a rich Sept. 11 widow is suspected of murder.

The death of a prison gang member leads Fontana and Green to suspect the victim's former associates until they learn the deceased also had a running battle with a hard-nosed corrections officer.

Detectives investigate the deaths of two college students and find both were participating in a pharmaceutical company's secret testing program for an antidepressant that has resulted in many suicides.

An illegal firearms sting backfires when two officers are slain, and Green poses as a gun buyer to try to capture the killers, who were able to identify the officers via a Web site identifying undercover cops.