Law of the Canyon (1947)

Bringing in a supply of goods, Steve has them hijacked. The Doctor is behind the hijacks and offers to act as a middleman and return the goods for a fee. He has doped up the Sheriff to keep him out of the way and now tries the same on Steve. But Smiley had earlier used the Doc's medicine in an experiment and replaced it with water and this gives the Durango Kid a chance to go into action.