While Mouch makes an incredible save, all eyes are on a mystery man who helped save his neighbour; Casey worries about his future at the CFD.
Severide and Casey try to find the best fit for Kidd; Ritter, Gallo and Violet help plan an event for Mouch.
Firehouse 51 deals with the aftermath of the capsized boat rescue; Gallo, Ritter and Violet discuss plans for a side gig.