After Tanjiro and his friends completed their training in Butterfly Mansion, they got a new mission to ride "Mugen Train". Forty passengers have disappeared in that train. Tanjiro, Nezuko, Zenitsu, Inosuke are ordered to meet up with one of the strongest swordsman, Kyojuro Rengoku the Flame Hashira. And the demons are waiting within the darkness on the Mugen Train.
