Officer Harper puts Officer Aaron through "Plain Clothes Day," but the exercise is interrupted by an unsuspected visitor.
Desperate to reset the way the world sees him, Officer Thorsen reluctantly decides to be a part of a reality show to help rebrand his image, only to be thrust back into yet another deadly situation.
A hazmat call at a dialysis center leads to a shocking discovery. Boden clashes with Paramedic Chief Robinson. Carver notices a concerning change in Gibson's behavior.
Mouch sets out to change his legacy and nickname. Ritter pushes Herrmann to see a doctor. Brett searches for the perfect wedding venue.
Firehouse 51 welcomes back some familiar faces and says goodbye to Brett. Violet scrambles to decorate Brett's wedding venue. A call at the expo center takes a shocking turn.