The school is suddenly transported to another world, where it is overrun by monsters and turned into hell. Okoyo Takumi, who lost his life while trying to escape with his beloved sister, Haruna, realizes that every time he dies he returns to the same time. Takumi is at the mercy of the monsters’ deadly siege and imprisoned in a prison of time that sends him back to the same time every time he dies. He continues to struggle, overcoming the rape and death of his loved ones time and time again. After successfully hunting an orc, a fanfare resonates in Takumi's mind.