The Flying Torpedo

In the future (1921), an alliance of several foreign countries plot to attack the US. American officials, coming to the realization that the country is basically defenseless, offer $1,000,000 to anyone who can come up with a weapon to defeat the invaders. Winthrop Clavering, a writer and inventor, hears of the reward and tells his friend Bartholomew Thompson, a scientist and inventor who has been working on developing flying torpedo. However, enemy agents have also heard about Thompson's project, and set out to kill him and steal his plans.