Receiving transmissions from a distant planet, Commander Krait wishes to communicate with the intelligent society on the planet designated as X-3-Z. Arn assists Dr. Triple when the Dr. interprets the language. The society on X-3-Z is prepared to wipe itself out in an aggressive war. Commander Krait sends Captain Jer to X-3-Z with a fleet of ships to try to stop the war. Once the fleet arrives, they are attacked. The fleet must flee as the war destroys the planet. Captain Jer reveals the inhabitants of X-3-Z called the planet Earth.