It has been five years since the Autobots defeated Unicron and rebuilt Cybertron. Now hundreds of Transformers have returned to their home planet to begin anew, while the threat of the Decepticons has faded into the past. Just as things are looking up, the Autobots are faced with a new enemy: the mighty Galvatron, who seeks to free the Chaos Bringer from his imprisonment so that he may finally destroy Primus once and for all.