The planet Libertia was once known as “the planet of death”, until humanity built three giant mirrors and created what seemed like an ideal land. It is on this planet that Professor Grace and his granddaughter Alcia live peacefully… until their home is attacked by Guild soldiers looking for the professor and for Legaciam – a special Armor that can resist extreme heat, allowing it to go to areas where humans would not survive normally. Alcia, who was at the time piloting Legaciam in order to help her grandfather with the testing, manages to get away… barely. But the Guild is determined to get Legaciam by any means necessary…

Even though the Decepticons have been driven off Earth, a small team of Autobot 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 Autobots' caution is rewarded: Decepticon Pretenders soon appear, led by a mysterious force called Devil Z. The Autobots and Decepticons soon build up their forces, recruiting humans to become Junior Headmasters and Godmasters (Powermasters).

In 356 BC, Alexander the Great arrives in Greece with the ominous destiny that he will become the "destroyer of the world." Inheriting the crown, he becomes king of the Macedonians and starts down a road of conquest with terrific speed. Alexander ultimately confronts his fated nemesis, Darius the Third, in a war with Persia which changes Alexander into the devil he was fated to become, assuring the destruction of all in his path, and possibly himself.

Summary of the first half of Gundam: G no Reconguista series.