Lt Casey must work with Voight and the Intelligence Unit, Shay grows increasingly excited about the prospect of motherhood, and everyone comes together to support the opening of Molly's.
The Firehouse 51 crew have their work cut out for them when a tornado hits city. Also, Brett must report Chili after she makes a big mistake.
Dr Halstead and Dr Manning are at odds over the care of a vegetative man. Dr Rhodes goes behind Dr Bekker's back to get his patient at the top of the transplant list. A woman in the waiting room falls asleep and won't wake up.
Halstead and Manning deal with arguing brothers, one of whom needs a replacement kidney. One of Dr Reese's patients comes to a crossroad.
Intelligence investigate a brutal attack on a family home, with a traumatised young girl as their key witness.