In a future where space travel is commonplace, Aries Spring embarks on a journey to planet McPa but encounters a thief at the spaceport. With the help of Kanata Hoshijima, she joins a group of teens on team B-5. However, their camping trip takes a bizarre twist when a strange phenomenon propels them into deep space. Alone and disoriented, they stumble upon an abandoned spacecraft that becomes their ticket home. But their return journey reveals a shocking truth—they are light-years away from Earth. Forced to rely on each other, the group must navigate the vast unknown, conserve resources, and stay united as they strive to find their way back aboard the Astra, facing unknown dangers and mysteries along the way.