A local drug syndicate known as the Caminos falls under attack by a masked vigilante called The Mantis, and Lassiter is soured by this since The Mantis has already made more progress than the police. Shawn is also put off, due to Juliet expressing an admiration for The Mantis' efforts. Shawn and Gus believe that a new cop is the vigilante, but as they put the pieces together, they start to believe that the Mantis' efforts may not be altruistic.

A billionaire that Lassiter investigated for murder avoids a jail sentence by means of an insanity defense. After he is sent to a mental hospital, Shawn and Gus go undercover as a patient and orderly to prove that the man is sane, but Shawn asks the question that Lassiter didn't even consider - what if the man is actually crazy?