Emilia is hurriedly ushered to the capital along with the villagers under the orders of a mysterious benefactor while escorted by a rag-tag group of individuals from various and opposing factions. She has but one question on her mind: who could this man be and why would he go so far? Meanwhile, Subaru and Julius face off against the Archbishop of Sin Betelgeuse for the ultimate time. Unfortunately, he is very persistent even beyond death, belying his nature of Sloth. Subaru is relentlessly chased while he catches up to Emilia to save her one last time and answer her question.

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?