When the key suspect in the Armenian money train robbery turns up missing, Aceveda discovers there is a mole in the treasury department who is feeding information to the Armenian Might. Vic and the Strike Team race to find the money train robbery suspect, who they originally framed, in order to keep the cover on their story. With the help of Diagur, the Strike Team finds their man, O'brien, and order him to get out of town before he's brutally cuddled. Meanwhile, the Strike Team realizes that O'brien has ignored their warnings to get lost and is still in town collecting on a sports bet. When they track him down, it's too late, the Armenians have reached him first. They must get rid of O'brien's body so that the Treasury department will continue to consider him the main suspect and investigate his disappearance.
The Shield breaks the conventional formula of the cop genre. It plays out in a tough, morally ambiguous world in which the line between good and bad is crossed ever day. The series focuses on the tension between a group of corrupt but effective cops and a captain torn between bringing them down and advancing his own political ambitions.
The Shield stars rogue cop "Det. Vic Mackey", leader of the elite Strike Team unit, who is effective at eliminating crime but who operates under his own set of rules. "Captain David Aceveda", the young precinct head who doesn't like Mackey's tactics and wants to bust him off the force. And "Det. Claudette Wyms", a veteran detective who understands Mackey and knows how to play both sides of the fence.