Maura Kidwell

After a 10-year-old boy is admitted to the hospital, Dr. Manning and Dr. Halstead disagree on how to best handle the boy's parents. Dr. Rhodes rushes to fix a heart that will be given to Dr. Reese's estranged father (guest star Michel Gill).

In the wake of Heather's (guest star Chaon Cross) incident, Lt. Casey (Jesse Spencer) is having a hard time handling his newfound responsibilities. Lt. Severide (Taylor Kinney) is on edge dreading the next attack from the firehouse’s arsonist. Meanwhile, with Renee (guest star Sarah Shahi) back from her mother's, Severide knows he has to confront her about his paternity suspicions. Elsewhere, Mouch (Christian Stolte) begins his campaign for union president and Shay (Lauren German) and Dawson (Monica Raymund) feel that they need to get out more.

Boden's (Eamonn Walker) future with Firehouse 51 is on the line and McLeod (guest star Michelle Forbes) keeps on him about his past wrongdoings, pushing him toward an early retirement. With Boden considering his options, McLeod calls on an unlikely candidate to potentially replace him as Chief. Meanwhile, it becomes clearer who the mole inside the firehouse is and everyone takes measures to make their disdain for him known. Meanwhile, Shay's (Lauren German) social life is in full bloom and Arthur (guest star Mike Starr) continues to take money from the struggling Molly's.

Kane’s moves with the housing project escalate from a state of unrest to rioting and looting. As Chicago burns, Kane secretly seeks treatment at an alternative clinic where his past haunts him. In Kane’s absence, his wife, Meredith, steps into the mayoral role.