After the events of The Headmasters, the Earth has been free of Transformers for several years, until the emergence of the Decepticon Pretenders. This group of villains were pursued to Earth during the Stone Age by a group of Autobots led by Metalhawk, and when both teams crash-landed on the planet, they used their special "Pretender" powers to adopt new disguises. Eventually, the Autobot Pretenders defeated the Decepticons and sealed them away, but as the series begins, they have been liberated from their prisons by the evil alien energy-being, Devil Z. With the return of the Decepticons, the Autobot Pretenders are forced to drop their disguises and take up arms once again. Both sides races to build up their forces, recruiting humans to become Junior Headmasters and Godmasters (Powermasters), to assists them in this new conflict. Source: TFwiki