The game takes place on the planet Cybertron, prior to the Transformers arrival on Earth. The Autobots and Decepticons are engaged in a civil war. The game can be played starting from either faction's perspective, but begins chronologically with the Decepticon campaign. The game revolves around the use of a substance known as Dark Energon, which the evil Decepticon leader Megatron believes will allow him to return the planet to what he refers to as a golden age. (wikipedia)