Michael, Lincoln and the inmates risk life and limb, the Vice President fears she will lose her command if not her life, and Veronica tracks down the most significant piece of evidence to prove Lincoln's innocence.
Sara considers whether she should help Michael with his plan, Michael betrays Warden Pope, and Veronica finds evidence that points her to Montana, but realises that her closest ally may actually be her greatest enemy.
Firehouse 51 responds to a suspicious call from a neighbouring firehouse, so Severide and Cruz investigate. Also, the team welcome a new firefighter.