Tracy Spiridakos

An airfield emergency triggers a deeper mystery involving a passenger plane, propelling the Intelligence Unit into a high-stakes pursuit of the culprit, all under the sharp eye of the FBI.

Firehouse 51 is called to an airfield when a passenger jet suddenly goes silent midair, triggering a high-stakes emergency; their discovery cracks open a bigger and deadlier mystery with consequences that could put countless lives in jeopardy.

The team investigates a drug deal gone bad after the body of a college student is found.

Hold On Tight. Kidd and Severide's honeymoon is interrupted by a dangerous person from their past. Kidd's former academy classmate joins Firehouse 51.

Infection Part 2. An entire apartment complex is forced into quarantine when cases of the deadly virus turns into an epidemic.

What I Saw. In the first part of a crossover with Chicago PD, a spate of robberies comes to light after a firehouse lockbox key goes missing. CPD's Voight has suspicions that a firefighter may be involved and with Boden's support he recruits Cruz to go undercover and help sniff out any suspicious activity.