On the way to a race the gang veers off to visit Debbie's Aunt Belle, a cattle rancher. The mysterious beefinger and his henchman have rustled up her entire herd. Speed Buggy and the gang rescue the cattle and try to drive them to the market.

Speed Buggy and crew help Professor Rigby, who is being attacked by his former colleague, Professor Rishna, after discovering an invisibility solution. Rishna uses it to kidnap Debbie and Mark while Tinker and Speed Buggy come to their rescue.

The crew visits Pleasure Island to enter the Bayou 500 racing competition. During the race, they find a ringmaster who plans to control all of the nearby animals in order to rule the world.