Sam Quint (Tommy Lee Jones) is a former thief hired by the FBI to steal a computer disk which contains incriminating evidence against The Lucky Dollar Corporation of Las Vegas. After stealing the disk, Quint is pursued by Marvin Ringer (Lee Ving), another former thief and acquaintance who works for the company. At the same time, a prototype vehicle called the Black Moon, which can reach speeds of 325 MPH and runs on tap water, is being tested in the desert by Earl Windom (Richard Jaeckel). Quint and Windom later cross paths at a gas station, where Quint hides the disk in the back bumper of the Black Moon. Windom is hauling the Black Moon to Los Angeles, and Quint, still being pursued by Ringer and his men, follows Windom and his team there.