In the wake of a devastating attack, the BAU works with former International Response Team member Matthew Simmons to save one of their own from escaped serial killer Peter Lewis.

Following the final incident with Scratch, the team has been taking a mandatory break to decompress. In addition, Reid has gone through his reinstatement evaluation, he who has been conditionally reinstated without the possibility of negotiation on that condition. In their time off, there has been a backlog of cases. However, they depart to Naples, Florida on a case of some currency, as a female has just been discovered murdered, her body stuffed into an old suitcase and placed in a public location. She is the second victim, the first as of yet an unidentifiable Jane Doe whose body had decomposed beyond a state of visual identification. By the time the team lands in Naples, a third victim is discovered. Beyond the suitcase in a public locale, the other similarities between the two identified victims is gender, that they were strangled, and that the same old fashioned shade of lipstick had been smeared on their mouth area. The lipstick and the suitcases indicate that there is some vintage aspect to the unsub's psyche, and that a probable stressor is being abandoned by a female, probably the unsub's mother when he was a child. They also discover that both women were in the process of a romantic evening, friends who can attest that they were careful women not prone to reckless dating. JJ surmises that the unsub is able to lure his victims unwittingly using a Florence Nightingale complex, in that they are attracted to some "broken" aspect to his personality. It isn't until the first victim is identified that a tie between all three victims is discovered. By that time, the team believes that the unsub probably has an ultimate victim in mind, who they have to discover before she becomes an actual victim. In the process of the case, Reid will demonstrate, at least in this case, if the evaluation committee was correct in their concerns about him.

The BAU team members head to Detroit, Michigan where two men in two weeks have been discovered dead. Both were married, Caucasian, mildly successful professionals. Both were found in very public places hanging by a meat hook, naked and their private parts cut off pre-mortem. The authorities eventually receive a snuff movie of the second victim, Curtis Wyler, including the entire time it took him to bleed out to death. The team analyzes the video in order to find any clues as to the unsub's whereabouts. Garcia discovers that both men had been systematically withdrawing large sums of money from their bank accounts, small enough not to be questioned by the banks. In questioning the Wyler's wife, the team believes that both men were probably using the money for the services of an escort. What Garcia finds is that it is not an escort service, but rather an online dating site, Blue Siren, where members arrange their own meetings. Both victims had been involved with the same member, a woman with the online handle Dasha, who had recently discontinued her membership. The team is able to locate Dasha, who admits to her involvement with the victims, but does not know why anyone would want to kill them. She is concerned that the unsub may be after her. The unsub is after her, but not in the way that she anticipates.

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

When Garcia experiences anxiety over a case that's personal to her from her past, Morgan visits to lend emotional support.

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

The team heads to Austin, Texas, where two women are abducted and disfigured, only to be located a day later with no recollection of what happened to them. A third emerges shortly after the team's arrival in Austin.

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 with 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 brutal casualties are reported in Central Park.

The BAU is called to investigate a series of D.C. homicides where cryptic messages are found inside the mouths of each victim.

The BAU is called when the New Orleans P.D. discovers a mass grave inside a vandalized above-ground crypt in a local cemetery.

The FBI's assistant director of national security, Linda Barnes, joins the BAU as they investigate a quadruple homicide of a group of roommates in St. Louis.

Away from the watchful eye of the FBI's assistant director of national security, Linda Barnes, the BAU meets in secret to investigate an UnSub who appears to be kidnapping and photographing young women.

The BAU is called to Oklahoma to investigate a murderous clown terrorizing the sleepy town of Guymon.

The BAU travels to Chicago to investigate an unsub who leaves red roses on each victim. Also, Rossi gets an unexpected visit from his ex-wife, Krystall Richards.

The BAU takes charge of a hostage situation at a law firm in D.C., where Matt Simmons' wife, Kristy, works.

The BAU is called to investigate a series of deaths in Virginia suspected by the Center for Disease Control to be caused by bio-terrorism; Garcia visits her stepbrother to take care of a family issue.

The BAU is called to Taos, N.M. to investigate an UnSub who is targeting his victims' temporal lobes.

When Reid discovers former FBI Special Agent Owen Quinn locked inside a storage unit, the BAU questions the credibility of Quinn's bizarre accounts of searching for an UnSub that he named "The Strangler".