Robot Masters

Even though the Destrons have been driven off Earth, a small team of Cybertron Pretenders have remained behind, just in case. Led by Metalhawk ("Hawk" in his human identity), the Pretenders live among the humans, using their Pretender shells to assume human size and appearance. The Cybertrons' caution is rewarded: Destron Pretenders soon appear, led by a mysterious force called Devil Z. The Cybertrons and Destrons soon build up their forces, recruiting humans to become Junior Headmasters and Godmasters (Powermasters).

Headmasters starts with Galvatron leading a new batch of Destrons to wage war on Seibertron, the Destron Headmasters. The Cybertrons are rescued by the arrival of the Cybertron Headmasters, led by Fortress (Cerebros, the head of Fortress Maximus). It is revealed that Fortress left Seibertron millions of years ago in search of energy, and have finally managed to come home. He explains that the Headmasters are from a planet called Master; the human-sized robots who live there built themselves Transformers-sized bodies. They can then transform themselves into the heads of the robots, and have now joined the Cybertron-Destron war.

An evil race of transforming robots known as the Destronger make their appearance known by invading a world exposition in New York and abducting Professor Onishi, a renowned scientist. The professor's son Yuuki befriends Fire Convoy and the heroic Cybertron forces, who will stop at nothing to rescue the professor and protect Earth from the wrath of Gigatron and his Destron henchmen.

The film revolves around the Maximals, led by Lio Convoy; the Predacons, led by Galvatron; and a mysterious device that has crashed on Planet Gaia (a future version of Earth), leading to the arrival of a legendary Maximal warrior, and the protagonist of the original Beast Wars series, Beast Convoy (Optimus Primal). Galvatron also uses the device to summon a monster Decepticon called Majin Zarak, who threatens to destroy all the Maximals.