Chicago Fire: Season 1, Episode 16

1 - 16: Viral

The anguish that haunts Cruz over his previous actions boils over, as he puts himself and his fellow firefighters in jeopardy. Casey and his sister Christie (guest star Nicole Forester) try to solve their issues with their mother (guest star Kathleen Quinlan) and each other. Severide reaches out again to an important person from his past as a favor to Lieutenant Whaley (guest star Shane McRae) and the squad gains new perspective after assisting the bomb squad on an extremely dangerous call.