Yuko Suzunari, who lost her girlfriend Takano in the lion accident, became a teacher at an elementary school in her hometown, but was losing her life goals. At that moment, the student Asumi and Fuchuno are separated by a walk. As they find the two and enter the forest, Suzunari remembers the story Takano once told about: "The secret base that was built when I was a child near the abandoned line in the forest." I looked for a cabin shaped like a rocket. And what I found in it...