The BAU team continues to unravel the clues given to each of them by a psychopath in order to save his most recent victim. Gideon decides not to focus on the personal aspects of the case. Rather, he tells the team to profile the killer as they would in any other investigation. Reid stays behind to work on a personal connection that could solve the case as one member of the team fights for life.
The BAU travels to Seattle to identify and catch a serial bomber who has been terrorizing the city and targeting centers of automated techology. Working with the author of a science fiction novel that has become a guide for the bomber, the team attempts to determine why certain sites have been chosen as targets.
The daughter of high-powered diplomats, Special Agent Emily Prentiss joins the team, and she must convince Gideon and Hotchner she deserves the job based on merit and not on her family connections. The BAU is then called to St. Louis to investigate two serial killers who appear to be competing with each other. By setting a trap based on one killer's profile, the team creates a media event by which to capture the second killer.
Gideon, Reid and Prentiss travel to Guantanamo Bay to interrogate the leader of a terror sleeper cell being detained there after a chemical weapons dispersal device is discovered during a raid at a suspicious house. Working with Reid, Emily's fluency in Arabic proves to be useful as they scrutinize the suspect.
The BAU is called to investigate the serial murders of prostitutes in Washington, D.C., and suspect a teenager is guilty of the crimes. The case becomes complicated when a congresswoman about to make a speech to praise the city's lower crime rate threatens to take away the case if Hotch calls a press conference to discuss it.
Gideon is pitted against the scariest and most evil murderer in his entire career. When the BAU confronts the sadistic killer in a remote diner in the Nevada desert, the local authorities want to move quickly and make an arrest. But Gideon bides his time as he attempts to persuade the man, who has sworn not be captured, to reveal the whereabouts of a woman he is holding hostage.
The BAU is called to investigate after a wealthy couple is murdered in their home following a Super Bowl party. The team pursues what they believe might be multiple killers who use webcams to record murders and upload the tapes on the internet. Hotchner, Morgan and Prentiss soon discover the unsub is actually one man with multiple personalities. As they close in on the killer, Reid faces a life-threatening situation.
A case involving a serial killer believed to be copying Jack the Ripper takes Gideon to New Orleans after three victims are found with their throats cut. Once thought to have been killed in Hurricane Katrina, the discovery of a fourth victim in the French Quarter confirms the murderer is still alive. All the evidence and files had been lost in the flood, so the only clue the team has is the word "Jones" that the lead detective wrote on the wall just before he drowned. Meanwhile, Reid meets up with an old rival as he continues to struggle with the aftermath of being held hostage.
The team investigates a serial killer who is targeting women at a small college in Flagstaff, Arizona. The BAU shuts down the campus, creates a detailed profile of the unsub, and arrests a suspect. However, the team members begin to have doubts about themselves when another woman is killed while the suspect is in custody.
In Milwaukee, a series of women have been found murdered with their hearts crudely removed. The BAU is assigned to the case, but they are short three members: Gideon, who is missing, Hotch, who is on suspension and Prentiss, who resigns her commission to join the Foreign Service. Supervisor Strauss steps in as lead, but she doesn't handle herself well in the field.
As the BAU searches for a suspected human trafficking ring when the bodies of two missing persons are found in the trunk of a car, Unit Chief Aaron Hotchner intimates there could be changes within the team due to budget cuts as Jennifer "JJ" Jareau returns to the FBI. The team is also assisted by SSA Andi Swan, the head of the Domestic Trafficking Task Force.
As the BAU team continues to pursue the bank-robbing serial killers, the team determines that the suspects have a bigger target in the nation's capital, and with one of the team still a hostage, they must work quickly to diffuse an explosive situation. Wedding bells ring for one of the BAU. Prentiss ponders her future.
When a Texas prisoner escapes during a transfer, he leaves behind victims with his unique trademark, sewing their mouths shut, a signature the BAU remembers as unique to the UnSub "The Silencer." While they investigate who he was and who he's become, the BAU also gets to know the newest member of the team.
When Hotch receives a phone call from his brother Sean while on vacation in New York City and several civilians are found dead from apparent ecstasy overdoses, the BAU attempts to profile a sociopath killer attempting to make a statement. Meanwhile, Hotch struggles to keep himself from becoming emotionally involved in the case.
As Hotch fights for his life due to complications from his stabbing at the hands of George Foyet, a.k.a. "The Reaper," he experiences visions of his late wife, Haley, and his nemesis, Foyet. Meanwhile, the BAU searches for a missing teenager and investigate her estranged father as a suspect in her disappearance.
After a series of victims are found strangled to death in Boston, the BAU looks for an unsub who likes to keep mementos of the victims, and the team wonders if a common link to the casualties could lead them to the culprit. Meanwhile, the BAU rallies around Rossi when his favorite bar is on the verge of closing.
Victims of arsenic poisoning are found in Long Beach. The investigation reveals that the killer has a fascination with Greek mythology, based on handwritten death threats to the deceased and other mysterious clues. Meanwhile, Hotch becomes concerned about participating in Jack's third-grade career day.
The BAU continues its murder investigation in Texas, and clues uncover a deep web of corruption that could be the motive for the killings. As one team member's life hangs in the balance, another concerned BAU member must face a sad secret from the past. Garcia is thrust into action to save a colleague.
When a family of four is abducted while on vacation in Barbados, the BAU is called to assist Unit Chief Jack Garrett and his International Unit on their investigation. Garrett and his unit, the FBI's top division for handling cases involving Americans abroad, work jointly with Hotch and his team when they discover that this case matches one the BAU investigated last year in Florida.
The BAU is interviewing different candidates to join their ranks in the wake of Kate’s departure, including a forensic psychologist, Dr. Tara Lewis, who is eager to assist their efforts. Also, the BAU hunts for a serial killer who leaves behind distinctive evidence that points to someone intent on revenge.
When the mummified remains of numerous victims are found in the walls of an elderly couple’s remote South Carolina home, Rossi, J.J. and Simmons are dispatched to track down a trail of clues that date back over 20 years. The hunt becomes urgent after BAU learns the killer has a specific ritual of when to strike, and like clockwork another person goes missing. Also, Rossi reconnects with his ex-wife, Krystall.
When packages with gruesome contents are delivered to six people in the Washington, D.C. area, the BAU must first figure out what connects the recipients before they can identify the UnSub. Also, Simmons and Kristy struggle to connect with their son, David, who is suspended from school for aggressive behavior.
Soon after the BAU steps in to help local law enforcement isolate a prime suspect for a ritualistic murder in Tallahassee, Fla., a second person who is related to the first victim is killed under similar circumstances. Also, Prentiss is concerned about Garcia’s behavior in the aftermath of her abduction and has an idea of how to help with the healing process.
The BAU investigates a spooky local ghost story of the “Tall Man” and the clues it provides when two people go missing in the woods of East Allegheny’s Dead Man’s Conservatory, and a third mysteriously surfaces the following day with limited details as to what happened to her friends. To assist with the case, JJ reluctantly returns to her hometown, triggering emotional flashbacks to age 11 and her older sister’s tragic death.
The BAU heads to Bethesda, Md., to investigate four murders in the span of three days along the eastern seaboard. The crimes become personal for Alvez, when the team discovers there are ties to his time spent five years ago working alongside the DEA and the Mexican police force in pursuit of the most notorious hitman in Mexico. Also, Alvez and his girlfriend, Lisa, decide to move in together.
Following an explosive face-to-face encounter with “The Chameleon,” Reid suffers from a brain injury and, while experiencing hallucinations, is visited by ghosts from his past. The BAU makes a shocking discovery about Lynch that affects Rossi personally. The entire team comes together to celebrate Rossi’s retirement.