When a scientist is killed in her laboratory, Hank and Wu investigate and discover that a strange incident ties together the dead woman with three of her colleagues. Meanwhile, the black-skulled creature attacks Eve, and Nick stands guard over her as she recovers in the hospital.

Nick and Hank investigate two seemingly unrelated crimes: a mystery killer of people on the street, and an orderly who claims that an elderly patient turned into a monster and attacked him shortly before she turned up dead.