The team goes on a city-wide hunt for an individual who is threatening a mass casualty event. Meanwhile, Tim's sister Genny shows up unannounced with some surprising news, and Lopez continues her inner struggle over Wesley's deal with Elijah and tries to come up with a plan to get them out of it.

Now that John Nolan knows about Bailey's past, he must decide if they still have a future. Meanwhile, when a plane crashes in the middle of the city the team races to find out why.