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.

When the mummified remains of numerous victims are found in the walls of an elderly couple's remote South Carolina home, Rossi, JJ 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. Rossi reconnects with his ex-wife.

The BAU investigates a double homicide and kidnapping in New Hampshire. Rossi's plans to elevate his relationship with Krystall don't go as planned.

Rossi questions his actions in the aftermath of a near-death struggle with a serial killer who appears to have outsmarted the BAU.

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.

Following an explosive face-to-face encounter with Everett Lynch, a.k.a. “The Chameleon,” 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.

With Rossi in Voit’s clutches, he grapples with the limits of his technical know-how and mental strength. As the BAU tightens their grip on Voit, he reveals just how far he’s willing to take his deadly crusade.