Two escaped convicts are found hiding in a rocketship built by a renegade inventor, who forces them to become the crew for a trip to the Moon. Also on board, as inadvertent stowaways, are his assistant and his secretary; and none of them are aware that the inventor is actually a Lunarian explorer sent to Earth by the dying Lunar civilization and the only remaining male member of that civilization.

Stunt driver Cliff Jordan takes a job with his old pal Jerry McGee, branch manager of an express trucking firm. Jerry is married to Mary, Cliff's former girl friend. Also working for Jerry is Pete Simmons, son of the owner Al Simmons, and office secretary Jane Chandler, who is Pete's sweetheart. Before long, Cliff has made enemies of Pusher Wilks, a trucker whose run he takes over, and also Pete, whose girl he is trying to take over. Pusher sabotages Cliff's rig at every opportunity causing several near-fatal accidents.

A private eye and his girlfriend avenge his buddy, stabbed over a jade dragon.