A major explosion occurs at Chicago Medical, where Casey and Dawson are volunteering at a charity run.
The Intelligence Unit works furiously to find the people responsible for an explosion at Chicago Medical. Voight and his team use their own angles and connections; Lindsay and Antonio interrogate doctors who operated on an ambassador from Syria; and Olinsky finds a lead. Meanwhile, the team realizes that additional bombs may still be active; and Burgess waits to learn about her niece's fate.
NBC's durable newsmagazine, featuring a mix of investigations, news updates and interviews.