Out in the desert, strange and evil things are happening. First, the house of Longwind Wilson suddenly disappeared. Then the house suddenly reappeared! Baffled by this, Longwind has called in Tom Mix, who has noticed that when Longwind's house reappeared - a giant cactus known as the Green Man which was located near the house - vanished! According to an old Indian legend, an old spirit lives in this cactus. Has the spirit of the Green Man come back to plague Longwind Wilson?