The story is about five people who run a public monster truck show led by Yank Justice, driver of Bigfoot. The other members of the show include Red & Redder (twin sisters who drive Black Gold), Professor Dee (driver o...展开f the Orange Blossom Special), and Close McCall (driver of War Lord). A young woman named Jennifer McGraw steals an ancient map that leads to the Fountain of Youth in Florida by a group of terrorists led by an elderly billionaire named Adrian Ravenscroft (a.k.a. "Mr. Big"), and they are attempting to retrieve the map from her. Ravenscroft hires a couple of workers who helped him try to get the map back named Ernie Slye and Ravenscroft's limousine chauffeur. This band of criminals chases Yank Justice and his friends across the United States and try to kill them.
In the end, Ravenscroft finds the Fountain and, after drinking its water, is turned into a young man, becoming a far more formidable opponent for Yank. But Yank and the others destroy the Fountain with their trucks, and Ravenscroft makes one final attempt to defeat Yank by trying to ram his limosuine into Yank's truck; however, Yank is able to move out of the way, and Ravenscroft's car is destroyed when it careens out of control. Ravenscroft tries to flee, swearing revenge, but the effects of the Fountain wear off and he is quickly turned back into his elderly self ... and is unable to see that he is walking into an alligator-infested swamp, presumably meeting his fate.
The scene then cuts to the rubble that once was Fountain of Youth and Jennifer bemoaning its destruction. Just as a disgusted McCall walks away, an earthquake forms a large crevice ... containing a huge fortune in gold, jewels and other rare artifacts. While he and several members of the Bigfoot team celebrate their discovery, Yank walks away ... and Jennifer joins him as they drive into the sunset.