Gekijouban Kimetsu no Yaiba: Mugen Ressha-hen Novelize

Tanjirou, along with Zenitsu, Inosuke, Nezuko, arrives at their next mission's destination, the Mugen Train, where over 40 individuals have vanished within a brief span of time. Teaming up with Kyoujurou, the Flame Hashira, Tanjirou confronts the hidden demon lurking within the train. However, what awaits them is an endless dream...!?

(Source: Shueisha, translated)