The setup for Transformers is two factions of sentient alien robots: the heroic Autobots and the villainous Decepticons. Both sides are from a race called Transformers - robots that can change into vehicles, mechanical devices and even animal forms. They have waged civil war for eons on their home planet of Cybertron, a war that had started several million years B. C. , before humans even existed on Earth. Their planet of Cybertron had become decimated and both factions have been reduced to scavenging for needed supplies, primarily energy. The Autobots leave their planet on a space ship, and the Decepticons follow them in their own vessel. When the Decepticons board the Autobot ship, a battle breaks out, and with nobody controlling the ship it crashes onto prehistoric Earth and knocks the Transformers unconscious. Millions of years later, in 1984, the dormant volcano the Autobot ship had crashed on becomes active. The eruption re-sets the ship's computer, which deploys a probe to study the planet. The computer learns that the planet is inhabited, and in order to survive first contact the computer both repairs the disabled Transformers and re-configures them with physical forms based on vehicles and machines of human origin. The Transformers are now able to hide by changing into vehicles or devices in case humans turn out to be hostile.