The main character, Kokone (13 years old at the time), enjoys watching airplanes at a small airfield on the island with a high school boy who loves airplanes, commonly known as Hi-kun. Kokone talks to GrounHand about Hi-kun's dream of becoming a mechanic, but he suddenly disappears... And 10 years later, the story of Kokone, who became GrounHand, begins to unfold.