On her 16th birthday, the unlucky, unmotivated and good-for-nothing Odagiri Yume saves the high-classed and lovely Momo, who claims to be the Devil. Yume confesses her wish to become special and Momo grants it: she makes Yume the representative of the Earth! However, Yume must now give Momo seven good reasons why the Earth shouldn't be destroyed, and the time limit is her 18th birthday. The countdown for the destruction of the world has begun and only Momo can stop it.