In 2005, Unicron, a roaming artificial planet, devours robot planet Lithone, and only two inhabitants flee. The evil Decepticons control the Transformers' homeworld, Cybertron. The heroic Autobots are using two of Cybertron's moons as staging areas, preparing to strike against the Decepticons. In need of energon cubes, an Autobot shuttle is readied for launch to Autobot City on Earth. A transmission is intercepted by the Decepticons, who ambush the shuttle, killing Brawn, Prowl, Ratchet, and Ironhide, intending to use the ship to infiltrate Autobot City.