AD. 2058, on the Clayad which was the 3rd planet of the Ypserlon system, which was 43 light years away from Earth, suddently aliens raided the planet.The emigrants on the Clayad had to escape from the planet. Because of the confusion during the escape, the children were strayed from their parents and got in the training space ship, Janous. With a lot of sacrifices, they managed to arrive at 4th planet Belwick. However, the Belwick had been already in the war. Therefore, the 13 children had to go to the Earth by themselves. Source: AnimeNfo