Sparks fly when "Biker" Bob Conway roars into town, looking for Frank and Joe. The motorcycle racer needs their help to prove his innocence in a hijack case. The problem is, Biker just escaped from jail. To make things worse, some very dangerous people are looking for him. One is a bounty hunter; the others are members of a motorcycle gang called the Sinbads. Frank and Joe can't leave a friend in trouble, and they defy their father in taking Biker's case. The brother detectives burn rubber in a high-speed race with both sides of the law -- where murder is the final pit stop.