Yukari Morita secretly visits the Solomon Islands during summer vacation to search for her missing father, Hiroshi, who disappeared on her mother's honeymoon. Meanwhile, the Solomon Islands Space Association (SSA) latest rocket, the LS7 has another launch failure. If they don't succeed soon, their budget will get canceled. The SSA director, Nasuda Isao, meets Yukari after tracking down an escaped astronaut. He talks her into becoming an astronaut on the LS5, a more reliable rocket that does not have enough power to lift a full adult.