After being attacked by someone the first time, sliced open by Elsa the second time, and stabbed in the back by punks the third time, Subaru should have been dead, but found himself back where he started in the same parallel world every time. He finally realizes he's acquired the power to go back to the time and place he started from, which he calls "Return by Death." In hopes of changing the fate awaiting Felt, Satella, Old Man Rom, and himself, Subaru takes off for the fourth time.

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?