After a failed assault on the Demon King, the Demon Slayers suffered many casualties. Subaru Natsuki, the Pain Hashira, was on the verge of ending it, but he failed. A month later, Subaru sees someone unexpected. A chase for answers ensues, but just before he could finish his target, he is thrown into the streets of an unfamiliar city. He meets a half-elf girl and his story begins