Fourteen-year-old Leo Beiderman (Wood) did not expect to make an earth-shattering discovery when he joined his high school astronomy club. He didn't expect to make any discoveries at all; he simply hoped that classmate Sarah Hotchner (Sobieski) would discover him. Yet a photograph he takes through his small telescope makes him co-discoverer of Comet Wolf-Beiderman... a comet that scientists determine is on a fatal collision course with the Earth.