It's the year 2038, but more importantly, it's summer. A young boy named Yuma is obsessed with the impending return of the SHIII-Arville Comet. Then, one day, he sneaks onto the roof of an apartment building and finds something even more amazing-something not from this world. Now Yuma and his friends, and his hovering autobot Nanako, must work together to uncover a secret that has lain dormant on Earth for years, as dawn breaks over a new era for him and for humanity...