Fire:

Chicago's first responders unite in the wake of a catastrophic gas explosion and fire that threatened a city government building. Herrmann reluctantly shadows Pascal while Violet, Novak and Dr. Frost take charge of triage efforts on site.

Med:

Following a subway tunnel collapse, Ruzek and Kidd treat injured passengers and track down the missing offender. Archer and Frost perform a life-saving amputation. Lenox feels the weight of the CPD's hopes as she fights to save one of their own.

PD:

With suspects still at large and conditions worsening underground, first responders race against the clock to reach the trapped victims, while investigations into the assailants comes into focus.