Frank and Joe go undercover as big-city bicycle messengers to crack a gang of high-tech thieves. Millions of dollars in computer secrets have already been stolen, and the brother detectives are hot on the trail.

Zipping through New York traffic at top speeds is dangerous enough, but one of their fellow messengers is out for their blood. Joe's bike is rigged with a time bomb, then a dispatcher is shot down. Unless the Hardys come up with a lead quickly, life in the fast lane could easily turn to death...