Tanjirou Kamado comes home to find his family slaughtered by a demon, and his sister Nezuko turned into one herself but still fighting to protect him. Determined to cure her and hunt down the demon responsible, he trains under a veteran swordsman and earns his place in the Demon Slayer Corps. This novel retells the story of Kimetsu no Yaiba in prose rather than manga panels or animation, following the same events as the original series.