Dio is a homeless man who lives with his dog, Loppe, in a giant train city.While Dio is a slow and calm person, all the average citizens are living their lives in a constant rush. One morning Loppe is taken by the trash collector, forcing Dio to start a chase throughout different parts of the place. As he struggles to save his only friend, Dio ends up defying the very nature of the city and its relentless way of moving forward.