The year is 2045, and the story is set in the Japanese-made space station "Anshin". A boy named "Toya" who was born on the moon and his childhood friend "Kokoro" are undergoing rehabilitation in the space station in order to move to Earth. However, they are involved in a collision between the space station and a comet along with Earth children "Tayo", "Miina" and "Doctor" who are traveling in space for the first time. In a closed space isolated from adults and cut off from the Internet, the children, who sometimes conflict and sometimes help each other, must face various difficulties together, such as decompression, EVA (space swimming), and micro-machine loss of control.