Aoba Watase is a normal first year high school student coming back to school after summer break when a mysterious robot comes after him. He has never seen it before, but its pilot seems to know him and wants him dead.
One minute, Hina is disappearing, telling Aoba that Dio is waiting for him. In the next minute, Aoba finds himself in a strange cockpit alone, thrust into the middle of a furious firefight.