Defcon 1

Summary

Lt. Severide has his strong ideas on who the serial arsonist is, but first needs to find proof to back up his suspicions. Meanwhile, Lt. Casey adjusts to his new lifestyle in the wake of recent events and Molly's bar is failing, much to the dismay of owners Hermann, Dawson and Otis. Elsewhere, Dawson goes out on a date with Jay Halstead, one of the bar regulars, and Mouch's campaign trail starts to get on track with the aid of Isabella, an old friend of Dawson's.

Guest stars

• Chaon Cross as Heather Darden
• Larisa Polonsky as Zoya
• Michelle Forbes as Gail McLeod
• John Hoogenakker as Lt. Spellman
• Mike Starr as Arthur
• Mena Suvari as Isabella
• William Smillie as Hadley
• Jeff Hephner as Jeff Clarke
• Jesse Lee Soffer as Jay Halstead
• Treat Williams as Benny Severide