The game takes place in the Western United States during a time of world-wide oil shortage in 1976. An organization known as OMAR (Oil Monopoly Alliance Regime) was making money off the shortage everywhere except in the United States. OMAR hires the best terrorist that $100 million could buy: Sid Burn. His job, aided by five hired Coyotes, is to destroy all gas refineries in the southwest of the U.S. so OMAR can bring the country to its knees. When gas prices went wild, six civilians who called themselves Vigilantes, led by the truck driver Convoy, began fighting against the Coyotes in different areas to keep OMAR from succeeding.

Vigilante 8 is a vehicular combat game similar to Twisted Metal in concept. Players can choose from eight characters with different agendas, and select vehicles ranging from classic 1970's muscle cars to a school bus, each stacked high with various kinds of weapons. Unlockables include two hidden levels (three in the Nintendo 64 version) and five hidden characters and cars. Multiplayer is also included: the PlayStation version allows two players (four in the Nintendo 64 version) to go head-to-head.