The story follows two children, Little Yu and Dafu, who venture into the city in search of their mother, who hasn't returned home in three years. By accident, they board a "Ghost Train" and follow the eccentric conductor, "Bone White," through a series of magical "special carriages." Suddenly, the train's assembly call sounds, and a large number of "Ghost Train Family" members begin to appear one after another. As the bond between "Red Oni Head" and Little Yu deepens, they embark together on a journey into an unknown world...