Daniel Kyri

Tensions run high between Casey and Herrmann after the firehouse responds to an apartment complex fire; after discovering something extremely suspicious during the call, Kidd and Severide do some investigating and get CPD on the case.

A series of teen opioid overdoses sees Severide partner with Sean Roman, but he begins to suspect there's more to the story than his old friend is telling him; Casey tries to be there for Brett as she considers her birth mother's offer to meet.

A series of mysterious gas leaks has members of Firehouse 51 puzzled and spread thin; Brett's conflicted when her birth mother gets serious about finding her; Severide misunderstands his role as Cruz's best man; Mouch bites off more than he can chew.

Severide teams up with Seager and the OFI when a motel structure fire turns suspicious; Firehouse 51 members become amateur sleuths following a Reddit post involving one of their own; Brett continues to get invested in her birth mother, Julie.

Things get personal for Casey and Gallo in the aftermath of a suburban house fire involving a mother and her young son; Herrmann campaigns for more respect; Kidd has an idea for giving back to her community.

The mattress factory fire spirals out of control; truck and squad lay it on the line in hopes of getting the trapped victims out alive.