The third-season opener picks up where the sophomore year ended, with Mannion struggling for his life after being shot on his boat and falling overboard into the Potomac River. As he tries to pull himself ashore, his would-be assassin, the daughter of the Russian mobster Putin, flees the scene and is hit by a car. While the accident reveals that Mannion is missing, the chief keeps his survival a secret to figure out who's behind the shooting. Deputy Chief Noland receives immediate pressure from an aggressive U.S. attorney general to solve the case, while a new press secretary tries to keep matters from spinning out of control.

Mannion goes head-to-head with the U.S. Attorney General and a tough civil-rights lawyer in an emotionally charged episode about child pornography. The investigation into the murder of an 11-year-old girl turns up the child's photo on a porn site, prompting Mannion to seek help from Attorney General Hatcher to toughen legislation against Internet child pornography. But Hatcher has an agenda of his own. In other cases, a congressman asks the chief to look into a case involving the alleged accidental death of his son, and a high-profile lawyer accuses an officer of using excessive force.