It is the Taisho Period in Japan. Tanjiro, a kindhearted boy who sells charcoal for a living, finds his family slaughtered by a demon. To make matters worse, his younger sister Nezuko, the sole survivor, has been transformed into a demon herself. Though devastated by this grim reality, Tanjiro resolves to become a “demon slayer” so that he can turn his sister back into a human, and kill the demon that massacred his family.
Tanjirou, Zenitsu, and Inosuke, aided by the Sound Hashira Tengen Uzui, travel to Yoshiwara red light district to hunt down a demon that has been terrorizing the town.
After a demon attack leaves his family slain and his sister cursed, Tanjiro embarks upon a perilous journey to find a cure and avenge those he's lost.
Tanjiro and his Demon Slayer friends join Flame Hashira Kyojuro Rengoku aboard the Mugen Train, where over 40 passengers disappeared without a trace.