Mia Park

As the city is thrown into chaos by freezing temperatures, Sylvie gets trapped in a life or death situation. Plus, an abandoned baby is found at the Firehouse.

Dr Manning investigates a young boy's background after the child is admitted with a broken wrist. Dr Choi tries to deal with an erratic patient.

The team find a surprising connection between two elderly patients presenting similar symptoms. Dr Manning loses her wedding ring.

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.

Halstead treats a woman on the verge of freezing to death, and Dr. Charles' ex-wife receives some concerning news. Plus Choi handles a lymphoma patient with viral meningitis and a complicated family, and Manning makes a house call.