While on a survey mission, the U.S.S. Enterprise discovers a comet is going to strike an inhabited planet. They try to re-route the comet, only to find that an ancient alien relic buried on the comet's icy surface is somehow stopping them. As the away team try to unlock the relic's secrets, Pike and Number One deal with a group of zealots who want to prevent the U.S.S. Enterprise from interfering.