The Decepticon leader Megatron returns from a three-year exile with a plan to exploit the properties of a mysterious substance called "Dark Energon", which has the ability to turn the bodies of dead Transformers into zombie-like Terrorcons. The Autobots storm an Energon mine in search of their lost comrade Cliffjumper, only to discover that his dead body has been revived as a ravenous zombie by Dark Energon.
Debuts: William Fowler, June Darby, and Decepticon Miners