Aziraphale (Michael Sheen) is an angel guarding the gate, while Crowley (David Tennant) is a fallen demon. The two have been living in the world incognito for thousands of years, and through continuous attempts, they have established a mutually beneficial relationship between heaven and hell. Crowley, under the order of Satan, sent the infant Antichrist to the monastery and exchanged it with the newborn of an American diplomat. When the Antichrist grows to 11 years old, the end of the world is coming. In order to prevent the world from being destroyed, Aziraphale and Crowley decided to avoid the end of the world by influencing the child's concept of good and evil. After 11 years of hard work, the two were shocked to find that they had made the wrong object, and the real Antichrist was living in a remote town called Tadfield.