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.

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.