The squad's former lieutenant, Al Giardello, is running for mayor and is close to victory when he is shot during a campaign speech. The assassination attempt inspires the arrival of the entire unit, past and present, in a joint effort to bring down the gunman. Every regular from the series—including two dead characters who make their appearance in a startling, non-flashback scene near the film's end—returns for this final chapter in the series' seven-year-long story.
