After a terrible earthquake, Satoru wakes up in a pitch black cave that him and his friends were exploring. Desperately moving through the crumbling cave with just his backpack, he expects a warm rescue once he gets out. But what awaits Satoru was an unbelievable fact: Japan has sunk underwater due to the earthquake and he is stranded on an island with no one to help him. Can Satoru learn how to survive by himself?

The world is in an uproar over the discovery of a stone tablet thought to have been created 500 years ago. The stone contains predictions of major incidents that happened worldwide in the last 500 years. All of its prophecies had already come true. There is only one prophecy recorded on the stone that pertains to the future ahead: that the world will end in a year’s time, and only those who believe in the god drawn on the stone will find salvation. The name of this god is… Myum-Myum.