Casey continues his run for alderman, but a citywide propaganda attack against his campaign makes him reconsider his candidacy. The rescue squad is summoned to the scene of a man trapped inside of a burning car with suspicious evidence suggesting that that the fire may have been intentionally set. Mouch's upcoming bachelor party looms, but with Trudy's nerdy brother Larry handling the details, everyone fears for the worst. Meanwhile, Jimmy and Brett take a kidnapping investigation into their own hands.