Will Salas (Justin Timberlake) and Silvia Weis (Amanda Seyfried) manage to break into Sylvia's father, Phillipe Weis's (Vincent Kartheiser), personal vault and steal a million years. They are able to release all of these years into the system at the ghetto.
Even though there's nothing the Timekeepers can do about the release, Raymond Leon (Cillian Murphy) continues to pursue the pair, but since Timekeepers only keep a small amount of time on their person and Raymond doesn't download his per diem during the final pursuit, Raymond's time runs out and he dies. Will uses Raymond's per diem to save his life and also save Sylvia's life in the same way he attempted and failed to save his mother's (Olivia Wilde) life early in the film.
Along the way, Will does away with gang leader Fortis (Alex Pettyfer) in a personal duel called a "Time Fight", where each opponent tries to drain the time from the other. Will wins by taking advantage of his opponent's split-second loss of concentration as his own clock nears zero. Fortis looks at Will's clock when it only has a few seconds left and Will, using this same technique that his father used to use, drains Fortis's time.
The ending implies that Will and Sylvia have become the Bonnie and Clyde / Robin Hoods of the new era, robbing banks to give time to the poor (much in the way Raymond told Will that Will's father used to do).
Thanks Evil Ed!