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

The BAU must determine what connects six people that each received a mysterious package in order to identify the Unsub. Also, Simmons and his wife Kristy must deal with their son, who got suspended from school.

Wedding bells are ringing as Rossi prepares to marry Krystall. But first, the BAU team travels to Los Angeles to investigate a series of fatal shootings in broad daylight following car accidents.

The team search for multiple serial killers. One who removes women's faces and another who cuts up men's torsos. J.J. and Spencer are still reeling after her admission. J.J.'s life is put in danger.

The BAU investigates seemingly random fatal explosions throughout Kentucky and Tennessee.

The members of the BAU enjoy a Saturday off in vastly different ways. While Rossi and Prentiss help Simmons assemble a new crib, Garcia leads a hacking competition, and Dr. Reid strikes up a conversation with a woman named Maxine

Series Finale. Following an explosive face-to-face encounter with Everett Lynch, Dr. Reid suffers from a brain injury and, while experiencing hallucinations, is visited by ghosts from his past. Also, the BAU makes a shocking discovery about Lynch that affects Rossi personally, and the entire BAU team comes together to celebrate Rossi's retirement.