Out of shape, with a bad leg and a serious drinking problem, Jack has a simple role on the force-clock in, clock out and stay out of trouble in between. When Jack shoves Eddie Bunker into the back of his car, he doesn't notice the van looming behind them. Jack stops Eddie's execution, killing one assassin, but when Jack calls for backup, homicide detective Frank Nugent is the first to arrive at the scene... and one of the detectives on his team is the man against whom he is supposed to testify.