Subaru and Rem are at a loss for words. The battle against the White Whale, which seemed to be going in their favor through attrition, suddenly took on completely different proportions. With their tactical superiority and advantage quickly dwindling, the combined forces all but get tangled up in the threads of despair. That's when Subaru decides to yell out his next move...

Suddenly, high school student Subaru Natsuki has been summoned to another world on the way back from the convenience store. With the biggest crisis of his life being summoned to another world, and with no sign of the one who summoned him, things become even worse when he is attacked. But when he is saved by a mysterious, silver-haired girl with a fairy cat, Subaru cooperates with her to return the favor. When they finally manage to get a clue, Subaru and the girl are attacked and killed by someone. Subaru then awakens in the place he was summoned and notices he gained the ability "Returns by Death" and has become a helpless boy that only has the ability to rewind time by dying. Beyond the despair, can he save the girl from the fate of death?