 "Day the World Ended" was released by American Releasing Corporation (later American International Pictures) as a double feature with "The Phantom from 10,000 Leagues".The film's storyline centers on a heroic scientist who, with a small band of other survivors, must face off against a mutant monster following an atomic war that appears to have destroyed human civilization.An atomic war has seemingly destroyed most, if not all, of human civilization, leaving the Earth contaminated with radioactive fallout.