Members of the firehouse are frustrated with their inability to help Chief Boden, whose job is on the line pending an internal investigation in the aftermath of a complicated call to a fire. Meanwhile, Lt. Severide struggles to accept his smaller role and adjusts to the presence of Capt. Patterson, his new commanding officer. Dawson shakes things up on the work front and Casey attempts to find a crucial piece of evidence in his ongoing investigation against Nesbitt. Elsewhere, Herrmann struggles to keep the peace with Molly's newest neighbors.