"Battle Ball," high-powered motorcross teams equipped with metal claws, protective armor, and a caged car which is used as the moving goal--has risen in prominence to become San Francisco's most coveted underground gambling sport.

While on a hunting trip, two friends witness a gangland style execution by Mr. Caine, a diamond smuggler. Garret and Paulie then become the hunted. Paulie is killed and Garret vows to avenge his friend's death.