Sam Quint, portrayed by Tommy Lee Jones, is a former thief operating under the FBI's direction to retrieve a crucial computer disk containing damaging evidence against The Lucky Dollar Corporation based in Las Vegas. Following his successful heist of the disk, Quint finds himself targeted by Marvin Ringer, another ex-thief—now connected to the corporation—played by Lee Ving. Simultaneously, Earl Windom, enacted by Richard Jaeckel, is testing the Black Moon, a revolutionary vehicle designed to achieve an astonishing speed of 325 MPH using just tap water.
Their paths eventually converge at a gas station where Quint conceals the stolen disk within the rear bumper of the Black Moon. Windom, who plans to transport the vehicle to Los Angeles, becomes Quint's only hope for evading Ringer's relentless pursuit. Once they hit L.A., Quint confronts FBI agent Johnson, played by Bubba Smith, insisting on doubled pay and a valid passport due to the escalating threat from Ringer. In an unexpected twist, Quint encounters Windom again at an upscale restaurant where negotiations for the Black Moon's sale are underway.
Chaos erupts when a gang of auto thieves, led by Nina, a character brought to life by Linda Hamilton, swoops in and swipes the Black Moon right from under Quint's nose. This forces Quint into a frantic chase, only to lose track of the thieves in a sprawling parking garage. Back at the restaurant, Johnson stresses the urgency of obtaining the disk within three days, or the case against The Lucky Dollar will fall apart. Failure to deliver means no pay for Quint, pressuring him into action.
Desperate, Quint approaches Windom for assistance, yet their plan to involve the police is swiftly dismissed. Taking matters into his own hands, Quint acquires blueprints of the Nyland Towers—a location doubling as a chop shop for stolen cars operated by Ed Nyland, portrayed by Robert Vaughn. After following Nina from the Towers to a nightclub, a budding relationship forms, but their shared illicit activities complicate matters further.
When one of Windom’s team is brutally killed by Nyland's thugs during their attempts to gather evidence, they decide to rally around Quint once more. A tense game of cat and mouse unfolds as Ringer bears down on Quint, demanding the return of the disk. After a fierce confrontation, Ringer narrowly escapes, raising the stakes once again.
Caught in a web of danger, Quint discovers Nina imprisoned by Nyland after she is labeled a traitor. He bravely rescues her, leading to a combined effort to reclaim the Black Moon. Following a series of thrilling escapades, including a raucous chase that sees the Black Moon careen through a building—ending in chaos for Nyland—Quint confronts Ringer in a final, climactic showdown.
Ultimately, Quint emerges victorious, reclaiming the disk just as Agent Johnson arrives on the scene. He makes it clear he’s done with the FBI after pocketing his hard-earned cash and heads back to Nina's apartment, where he playfully contemplates their misadventures. With a shared acknowledgment of their thrill-seeking exploits, they both find a sense of satisfaction in their escapades with the Black Moon.
