Members of Firehouse 51 are less than thrilled when Captain Patterson steps in as replacement for Chief Boden while he deals with clearing his good name. When Severide learns of the potential whereabouts of Serena, Chicago P.D's Officer Atwater and Officer Ruzek head to Lake Carlyle to try and uncover additional clues on Boden's case. Meanwhile, Herrmann and Otis give Freddie a job that keeps him close by and Jimmy and Chili elicit more attention then either bargained for, causing some friction between them.