A gigantic meteorite heads for Earth. Captain Simmons and Lieutenant Roy in the U.N. Guard Patrol ship, U.N. Patrol Ship 88, are ordered to check out the object by Space-Admiral Jennings. When they arrive, it is an enormous pock-marked meteorite. Roy estimates its diameter at about 500 miles. It is headed toward the Earth at 25,000 miles-per-hour. Simmons decides to land the Rocket on the meteorite. As they land, they receive another message from the Admiral. Earth is being evacuated in anticipation of the meteorite's impact. This impact is calculated at less than 5 days.