Tonight's The Night
performed by The Shirelles

During a frigid, cold night in Chicago, Firehouse 51 responds to a car crashing into a power line when suddenly the power line fail and sends the entire grid into a blackout. Boden and the others provide safe haven to those without power. A fight breaks out in the station and Severide disarms & kicks out the instigator responsible. CPD detective Erin Lindsay makes a surprise visit and reveals the man Severide disarmed is a known criminal name Vince Keeler, who wants revenge for humiliating him. Keeler send a hitman to kill Severide, but failed, thanks to the intervention of Casey and Lindsey. Casey shows symptoms of memory loss since his life-threatening injury. Cruz sends Clarke to a corner store to get some food, but the store gets attacked by looters. Then Severides's sister Katie gets abducted.