The BAU head to Miami to find out more about a serial killer with a seemingly conflicted sexual identity and JJ's secret is revealed.
Bobby meets Athena's parents for the first time, while a tanker carrying a shark crashes on the freeway. Maddie attempts to end her marriage for good, which ends up causing Doug to insinuate himself even deeper into Chimney's life.
The team search for a boy from Ralph's class who goes missing during a field trip. Toby gets closer to uncovering the identity of Happy's husband.
Vivien and Violet find themselves in a dangerous situation eerily similar to a past event. Ben goes back to Boston to fix a mistake.
The line between the living and the dead blurs on Halloween. Two of the house’s previous residents give the Harmons decorating advice.