Season 4 Episode 9
"Short and Fat"
Patterson replaces Boden as chief; Dawson becomes a target of the conspiracy; an act of violence will change 51 forever.
After Boden's (Eamonn Walker) recent arrest, Riddle makes Patterson (Brian White) the new chief at 51. A video of Dawson (Monica Raymund) exchanging heated words with a bystander goes viral, and is traced back to Roger Maddox, the real estate developer and focus of the arson case. Dawson is the latest target of Maddox's smear campaign - which now includes Boden, as well as Duffy and Suzie from Arson. Severide's (Taylor Kinney) lawyer friend, Jamie, has a change of heart and provides him with a tip to the location of Boden's mystery accuser. With the help of Chicago P.D. and the Intelligence unit, the mystery woman is found, and she confesses to falsifying the claims against Boden. Maddox, confronted with the evidence, cops a plea and all charges against Boden are dropped. Patterson, having seen 51 rally around Boden, decides on a transfer to a different firehouse, and Boden is reinstated as chief. Severide is also reinstated as a lieutenant.
Chili (Dora Madison) and Borrelli (Steven R. McQueen) are busted by Patterson, after he catches the two of them in the firehouse shower.
In one of Patterson's last moves as chief, he tells Cruz (Joe Minoso) that his friend Freddie is no longer welcome at 51. Herrmann (David Eigenberg) then offers Freddie a job as a busboy at Molly's. In a shocking cliffhanger, Freddie stabs Herrmann after he feels insulted. Herrmann collapses, and Freddie flees into the night.