Lindsay goes undercover at a casino. She's pulled over on her way home by a cop who tries to steal her winnings. Halstead and Atwater arrive to arrest him.
He's not a real cop. His badge is stolen.
Burgess requests a transfer and Platt tries to talk her out of it.
A casino victim talks to Voight and Lindsay, but the guy they have is not the guy who attacked her. They realize there's a crew of fake cops and get a name, Clayton Howard, from the guy in custody. The victim identifies him.
Burgess and Roman head to his house. They end up in a car chase and they crash.
Ruzek and Atwater go to the casino to try to find the spotter in the robberies. They track him down and find him dead.
They track down another member of the crew and Roman and Burgess go to her house. Roman chases Howard while Burgess arrests the woman partner.
Howard gives up the name of the cop who was behind the whole thing - Watts, who was working the case.
They go to Watts' house and find his money and talk to his wife.
Platt asks Voight to let her bring him in.
Watts tells her his story of why he did it. Platt talks him out of killing himself and she arrests him.
Lindsay asks Burgess to really think about her transfer request.
Mouse sets up Ruzek with a new girl, but he tells her he's not ready.