Yukiteru, a lonesome recluse, fills most of his time by writing a diary on his cell phone. His only friend is imaginary, a god called Deus Ex Machina. However, Deus who turned out not to be imaginary now wants to play a game with Yukiteru, a game of survival. There are twelve contestants with Yukiteru being the first of them. The winner of the Survival Game will succeed Deus Ex Machina as the god of time and space. In order to win the game, the contestants must use their diaries to eliminate one another, and be the last man standing. For Yukiteru to survive, he must team up with another diary holder, a girl by the name of Yuno.