While checking out a warehouse as part of his Alderman's duties, Lt. Casey finds himself in a bad spot when a forklift accidentally pierces a tank storing acid causing an extremely hazardous spill. With a father and daughter in peril, Casey is forced to use extreme measures to remedy the situation. Dawson and Brett respond to an elderly woman who has a difficult senior advocate. Meanwhile, Mouch and Brett continue along with their secret project together and Otis shares some exciting news as he prepares himself for an unusual expedition.