With the battle against the White Whale now over, the mercenary force setting up the blockade of the road comes back, Julius at the lead. His arrival gives rise to mixed feelings for Subaru, but after Julius sincerely thanks him for ridding the world of the monster, Subaru finds it in himself to apologize for his past behavior. The group now looks forward, ready to enter the Mathers domain...

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?