4 million years ago, after years of civil war that devastated their home world of Cybertron, a race of sentient transforming robots known the Autobots, led by Optimus Prime, fled their planet in search of resources. Their rivals, the Decepticons, led by Megatron, followed and a battle ensued that resulted in both factions crashing to ancient earth. In 1984 they awoke and continued their battle, now with the fate of Earth hanging in the balance. The Decepticons spent years plundering Earth's resources and were able to defeat and expel the heroic Autobots from Cybertron. In 2005, the Planet-Sized Transformer known as Unicron attempted to destroy Cybertron, but was killed in the process. The Autobots retook Cybertron, under the command of their new leader Rodimus Prime, and the Decepticons were expelled to the planet Charr, serving under the rejuvenated Megatron, now known as Galvatron. In spite of this, the war rages on and now the entire universe is their battlefield.