Encounter.Aoba Watase is a normal Japanese first year high school student coming back to school after summer break when a mysterious robot from the future comes after him. He has never seen it before, but its pilot seems to know him and wants him dead. His classmate Hina Yumihara appears in a giant robot of her own. She rescues him and tells him to get inside the cockpit. She defeats the mysterious robot but after Hina explained what happens to Aoba, the mysterious robot wakes up then clings to Hina's mecha, the pilot initiates a self destruction and tells Hina that she's going to die together with Aoba Watase and him. Meanwhile, a time vortex appears in the sky, Hina decides to bring them enter the time vortex. Inside the time vortex she tells Aoba cryptically "You're going to the future now, Dio is waiting," before she disappears. When Aoba wakes up, he finds himself in a strange cockpit alone, thrust into the middle of a furious firefight.