Gallo clashes with the new lieutenant temporarily filling in for Casey. Severide closes in on a dangerous and deadly arsonist.

Patterson fills in for Boden, who’s trying to clear his name. Severide learns where Serena may be hiding. Herrmann and Otis give Freddie a job that keeps him close by….

Boden’s job is on the line pending an internal investigation. Severide adjusts to Patterson, his new commanding officer. Dawson shakes things up at the work. Casey searches for important evidence…

Evidence that seems to exonerate Boden may not be enough. Brett and Chili find themselves in a precarious situation. The team responds to a stuck elevator in a hotel. Jimmy…