Victims of arsenic poisoning are found in Long Beach. The investigation reveals that the killer has a fascination with Greek mythology, based on handwritten death threats to the deceased and other mysterious clues. Meanwhile, Hotch becomes concerned about participating in Jack's third-grade career day.
As Hotch fights for his life due to complications from his stabbing at the hands of George Foyet, a.k.a. "The Reaper," he experiences visions of his late wife, Haley, and his nemesis, Foyet. Meanwhile, the BAU searches for a missing teenager and investigate her estranged father as a suspect in her disappearance.