Subsequent to a severely destructive earthquake, a boy dashed into his bedroom room because there remains his last happiness—a snow globe given by his mother— in the last closet drawer. Since his mother passed away, he has been immersed by an air of melancholy for ages. When the boy pulls the drawer out, the first sight astonishingly descends on him that despite the cracked snow globe, there is a new galaxy, in which two planets are floating in solitude. Staring at the unconnected planets for a while, the boy collects the scattered blocks to create a bridge and picks up his little postman into the galaxy. As soon as the postman touched the world, he comes alive. The postman embarks on an unknown journey. From Sunset Planet to Steam Planet, the postman encounters a group of Sunset Planet citizens and then share their blissful love and happiness with Steam Planet Citizens. In return, the postman harvests diligence and courage.