We pick up where we left off from the season 10 cliffhanger, Langston is on the floor of Haskell's cell bleeding to death and is rushed to the hospital where he is stablized. Nick goes to Officer Clark's funeral (killed in episode #1023) to pay his respects but watches from a distance since the officer's family feels he is partly to blame for his death. While waiting in his car, Nick notices a ticking sound coming from a nearby van. Almost simutaneously the officers castket explodes, then another explosion. Family members and officers are running from the explosions right toward Nick who is trying to warn them not to come his way when the van explodes. As the team investigates the attack, Brass and Langston, who is helping with investigation from his hospital room, initially think Haskell is involved. With the help of the new BABE (Ballistics, Arson, Bombs, Explosive technician), Kacey Monahan, the team pieces together the remniants of the bomb and the cell phone detonator. They trace the cell phone back to a radical anti-government group who attack Brass, Sara and a team of officers when they arrive at the groups community center; Brass takes everyone in for questioning. A young boy in the group, Jason McCann (Justin Bieber), has something to hide. Nick befriends Jason and Jason finally tells him that his brother Alex was the bomber. The team tracks down Alex who pulls a gun on Nick and the team. They are forced to open fire and kill Alex. Just when everyone thought it was over, Catherine, Vartann and Greg get called to an abandoned warehouse where they find a murdered homeless man has been booby trapped. Catherine watches Vartann and Greg get caught directly in the explosion. Catherine knows this isn't over.