In the aftermath of a riot, cops are being lured into ambush shootings by a rash of bogus 911 calls. Surprisingly Mackey and Captain Aceveda must work together to stop these attacks and solve the problems in The Grove, while Assistant Chief Gilroy tries to pit the two against each other to save his own job.

As time passes in the Chicago house, Tonya becomes more removed from the group. Her illness has kept her from group trips, from participating fully at work and from becoming a part of the close-knit group of friends. When she informs them that she can't go on the trip to New England, the gang wonders whether or not she is using her sickness as an excuse because it just so happens that Justin is coming to Chicago at the same time. While everyone else makes fun of Tonya when she's not there, Theo has had enough and lets her know what he and everyone else thinks about how she's handling things. The argument brings Tonya to tears.
When Justin arrives, he confronts Theo about the incident. The two have an intense discussion and come to some agreement. Justin tells Tonya that she needs to avoid interacting with Theo and she gets defensive. Later, when the gang leaves, Tonya and Justin argue about Tonya's friend Darren and her relationship with him. Justin thinks it's weird that Darren calls

Tonight, reporter for MSNBC, Ashleigh Banfield.