The bodies of two missing persons are found in a car trunk, and the BAU suspects that an interstate human trafficking ring is at work. Also, Hotch warns the team of possible changes, and they are surprised when a beloved team member returns.

The BAU is Florida-bound to investigate bodies discovered buried in the ocean floor off Jacksonville, but the case rattles Morgan when his aunt suspects that her missing daughter is one of the victims.

The BAU is called to a North Carolina mountain town after a woman is found badly injured and another is missing, and they discover that these two are not the only victims.

The BAU hunts a stalker in San Diego who is targeting college students. Meanwhile, the team comes under Strauss' scrutiny in the wake of the loss of Prentiss.

As the BAU investigates targeted killings in Tampa, they also deal with their own feelings about the loss of Prentiss.

When a gang of suspected murderers begins targeting a new victim each night, the BAU travels to Portland to head them off before they can strike again.

Prentiss is ready to confront her nemesis, Ian Doyle, once and for all. Meanwhile, the BAU calls upon JJ to help them find Prentiss and capture Doyle before it's too late.

After a series of suspicious murders occur, Prentiss suspects her old Interpol nemesis, making her fear for the safety of her BAU team as he closes in on her.

Reid makes a connection with an autistic child that could assist the BAU in finding the boy's missing parents. Also, Prentiss enlists two former Interpol colleagues in hunting an old nemesis.

The BAU is called to upstate New York to investigate mysterious disappearances. Also, Prentiss gets some disturbing news about one of her former Interpol colleagues.

The BAU travels to Los Angeles to investigate unusual murders throughout the city. Also, more of Prentiss' mysterious past comes to light.

The BAU hits the road to track down a pair of young lovers on an interstate murder spree. Also, Prentiss hears frightening news from her former boss at Interpol.

As the BAU travels to Miami to investigate a series of bizarre, ritualistic murders, Reid suffers a series of blinding headaches and hallucinations that leave him concerned for his health.

Morgan suggests that a man has been rehabilitated and aids in his parole, but later regrets his decision when the man murders someone days after being released.

The BAU searches inside a gated New Mexico community for a killer targeting women, and Hotchner looks to an FBI cadet with a unique past for help with the investigation.

When an 8-year-old is found murdered on the Appalachian Trail, the BAU team goes deep into its forests in search of a man lurking in the wilderness who is targeting children.

When a kidnapped woman is found murdered in an alley in Georgetown, the BAU team goes on the hunt for the killer before he can strike again.

When bodies begin turning up in the cornfields of Indiana, the BAU team must catch a pack of serial killers targeting exotic dancers.

The BAU team must find a killer who has struck Detroit for the past three years solely during the raucous pre-Halloween celebration "Devil's Night".

The BAU team is on the trail of a serial killer targeting families throughout the Midwest. Meanwhile, Morgan is concerned when Ellie runs away from her foster family and pays him a visit.

The BAU team searches for a serial killer who is preying on married couples. Also, Hotchner looks to one of the team to fill JJ's vacant role.

When several women are found murdered in a similar fashion, Rossi revisits a cold case that has haunted him for 25 years, causing him to suspect that the original killer is at work again.

While JJ attempts to reunite a family whose daughter has mysteriously disappeared, her BAU family braces for the loss of one of their own.

The BAU team closes in on the serial killer as he continues his murder spree throughout Los Angeles - with Detective Spicer's kidnapped daughter as his hostage - in the conclusion of last season's cliffhanger.