Michael tries to figure out how to tunnel in a building that houses a guards' break room, Kellerman and Hale attempt to kill Veronica and LJ, and T-Bag tries to dodge responsibility for Bob's murder.
With Lincoln's execution now just a day away, Michael looks for a way to get him out of solitary confinement in time for an escape. Meanwhile, Veronica comes out of hiding and gains an ally.
Voight and the team race to solve a gang shooting witnessed by Olinsky's daughter, fearing she could now be a target.
Detective Lindsay calls in suspects in the disappearance of Katie's kidnapper, Jones struggles to fit in, and Herrmann celebrates his 20th wedding anniversary.
Boden tries to keep the firehouse from closing, the romance between Dawson and Casey grows, Cruz worries for his brother's safety, and Severide and Katie make up for lost time.