"There had been no wars for centuries!" Space Force is an Earth based military force along the lines of the Army, Navy, and Air Force. Cataclysmic events threaten to cause great damage on Earth. A disturbance originating on the Moon is the cause. Major Dan Barton, Lieutenant Joe Turk, and Lieutenant Larry Cotton go on a mission to the Moon to discover the cause of the disturbance. Observing that the Moon is in the throes of violent earthquakes, which might be caused by "power guns". Major Barton reports by video message. The decision is made to send an Armada from Earth.