Danny is called to the scene on Halloween night, when a man in a priest costume is attacked by a figure dressed as a skeleton. Detective Kate Lansing is assigned to help on the case and she recognizes the skeleton costume as the garb of Baron Samedi, a Haitian spirit of death. With the suspect's photo taken from video surveillance, they visit the Haitian temple and speak to a priestess who identifies the culprit as a young man named Toussaint Lazard. They track Lazard at his apartment but he throws a cross at Danny before escaping through the window. The cross bears the inscription of a priest's name, leading them to believe Lazard was targeting this man instead of the victim who was dressed as a priest. They find Father Fran Ainsworth, the owner of the inscribed cross and an exorcist who had repeatedly tried to help the troubled Lazard. Danny and Kate locate Lazard at the Haitian temple and arrest him as he convulses violently. Danny has suspicions that Lazard was actually possessed while Kate believes he was on hallucinogens. Meanwhile, Frank helps Garrett avoid resignation when he becomes the target of extortion and Jamie becomes invested in helping a volatile mental patient. Jackie decides to take a leave of absence.