The exploits of a group of men and women who serve the City of New York as police officers, firemen, and paramedics, all working the same fictional 55th precinct during the 3pm to 11pm shift - the 'Third Watch'.
The series concludes with the gangbangers taking out their assault on the 55th Precinct. After some grenade explosions, the precinct is destroyed. Cruz knows that Marcel Hollis is behind the attack, and she takes his life, as well as her own. Carlos proposes to Holly, and they are married. Everyone receives their reassignments, and Sully retires. In the last few moments, Sully narrates a look into the future.