Lt. 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…

While Pete and Claudia travel to Oregon to look for an artifact used to kill enemies of the environmental movement, Artie deals with the repercussions of Leena’s death.

Speedle and Delko are present when a trendy nightclub catches fire, apparently from a DJ’s pyrotechnics display, killing sixteen people and injuring dozens of others. But the ensuing investigation reveals…

The investigation into the death of a pregnant teenager exposes a long-held family secret which precipitates another violent death and the destruction of two families.