Since ancient times, rumors have abounded of man-eating demons lurking in the woods. Because of this, the local townsfolk never venture outside at night. Legend has it that a demon slayer also roams the night, hunting down these bloodthirsty demons. For young Tanjirou, these rumors will soon to become his harsh reality ... Ever since the death of his father, Tanjirou has taken it upon himself to support his family. Although their lives may be hardened by tragedy, they've found happiness. But that ephemeral warmth is shattered one day when Tanjirou finds his family slaughtered and the lone survivor, his sister Nezuko, turned into a demon. To his surprise, however, Nezuko still shows signs of human emotion and thought ... Thus begins Tanjirou's quest to fight demons and turn his sister human again.
Sejak dari zaman kuno, tersebar khabar angin dengan luas raksasa membaham manusia menghendap di hutan. Disebab-kan ini, penduduk tempatan tidak ke luar sewaktu malam. Legenda pembunuh raksasa juga merayau-rayau pada malam hari, memburui raksasa yang haus darah. Bagi Tanjirou muda, desas-desus tak lama lagi berubah menjadi realiti penuh kepayahan ... Sepemergian ayahnya, Tanjirou terpaksa menampung sara hidup keluarganya. Biarpun semakin susahnya kehidupan mereka akibat tragedi, mereka mengecapi kebahagiaan. Namun nikmat yang seketika itu berkecai suatu hari tatkala Tanjirou dapati keluarganya terbunuh dan sebagai satu-satunya orang berikhtiar untuk hidup, adik perempuannya Nezuko, menjadi seorang raksasa juga. Mengalami kejutan kepada dirinya, tetapi, Nezuko masih menunjukkan tanda emosi manusia dan pemikiran ...