In 2011, a radio station in California made a bold, widely publicized prediction that the world would end on May 21. As the date approached, followers of the station's leader, Harold Camping, prepared for the rapture, some even quitting their jobs and making significant life changes in anticipation of the event. The documentary explores the psychology of belief, examining how people can become so deeply invested in a conviction that they are willing to ignore evidence to the contrary and how they justify their beliefs even when they are proven wrong.