Two LAPD cops, Detective Mitch Preston and Officer Trey Sellars, both from the Central Division, are paired for a television police reality show and run into trouble with a crime lord. Mitch shoots a news camera after a failed confrontation with local drug dealer Lazy Boy, who escapes by using a custom-built gun. Maxxis Television, the network that employed the cameraman, decides to sue the police department for $10 million, but will drop the lawsuit if Mitch agrees to star in the police reality show, which Trey soon calls Showtime!
[Trey] is an LAPD officer who wants to be an actor while also trying to become a detective. He devises a staged purse snatch of the show's producer, Chase Renzi, then retrieves it after a fake fight scene. Although the deception is embarrassingly revealed, Chase signs him anyway. It becomes clear that the show's producers care little for genuine police work: they build a mini-movie set in the middle of the station, replace Mitch's ordinary car with a Humvee, and hand Trey a flashy C5 Corvette. They even hire William Shatner to coach the pair on acting. But while Trey is eager to learn, Mitch is annoyed.
Despite all this, Mitch tries to investigate the mysterious supergun, which is used by arms dealer Caesar Vargas to kill the drug dealer and his girlfriend. Through a clever ruse by Trey, they obtain the arms dealer's name from Re-Run, the dead dealer's henchman. Vargas is reluctant to cooperate, leading to a nightclub brawl. Trey and Mitch defeat him and his men, and share a relatively friendly conversation on the way home. However, Mitch's good humor vanishes when he discovers that the Showtime! producers have remodeled his house and given him a retired K-9 as a pet.
Vargas and his squad ambush an armored car, killing the crew and devastating the police who respond. Trey and Mitch arrive and are pulled into the firefight. When the attackers flee in a garbage truck, Mitch chases in a police car. The ensuing mayhem ends with the police car being rammed by the garbage truck, crashing into a construction site. Mitch survives by leaping from the police car to Trey's sports car (he had previously denounced “hood-jumping” as a useless skill). In the wake of the disaster, the police chief pulls the plug on the show, suspends Mitch from duty, and demotes Trey back to patrol.
With the show ended, Mitch's car is returned and his apartment restored (but he refuses to return the dog, of which he has grown fond). While watching the final episode, Mitch phones Trey and apologizes for his actions, offering to help him ask questions on the detective exam. However, while doing so, Mitch sees one of his police colleagues at Vargas's nightclub. He and Trey investigate, finding that Vargas is selling the weapons at a gun show at the Bonaventure Hotel. Vargas flees with one of the weapons, taking Chase hostage in the process. The duo rescues her via a pocket pistol concealed in a Maxxis camera, but the ceiling of the room is shot. It is located just below the pool, so it floods, and Vargas is washed out the window to his death, but Trey and Mitch manage to survive by handcuffing themselves together. They end up suspended from a broken beam outside the hotel.
[Trey] is promoted to detective, he and Mitch are now partners and still working together with a new case, and there are hints of a romance between Chase and Mitch. Showtime! is revived for a second season, this time with two young and attractive female officers who are just as antagonistic as Mitch and Trey.
