One night, right before summer vacation, Manatsu Daichi, a second-year in highschool , sees a weird round rainbow floating within the sky above Tanegashima and ventures there alone. He has seen this rainbow before. With the memories of his father’s mysterious death and an encounter of a wierd boy and girl, Daiji arrives on the island while the alarm of a building labeled Earth Engine goes off. Someone asks him if he’s a captain, even as robotic intruders from Uranus called Kill-T-Gang arrive. The battle round the shining stars is close to begin.