The Mystery of Lost Ranch (1925)

Two men claiming to be scientists arrive in Arizona looking for Blair, a fellow scientist who disappeared while developing a death ray. The men hire Jim Wilson (Pete Morrison), who finds Blair living with his daughter on a ranch in an inaccessible valley near the Grand Canyon, where the scientist is testing his ray on birds and wild animals. Jim then discovers that the two men from the East are, in reality, agents of a foreign government, who hope to steal Blair's invention. Jim quickly sides with Blair, defeating the foreign agents with the help of Blair's daughter, whom he comes to love. Jim hands the agents over to law officers and returns to the ranch in Lost Valley.