Transformers: Generation 1

The operation to merge the Autobots and Nebulans into Headmasters proves to be a success when they go to rescue their captured friends. But the Decepticons join forces with the Hive to become Decepticon Headmasters and Targetmasters. While on Cybertron, Optimus Prime merges with Vector Sigma and he discovers the deadly secret of Plasma Energy. But this information may have come too late for Zarak, evil leader of the Hive, succeeds in converting the Hive's entire city into a Decepticon super robot, the most powerful ever created, the deadly Scorponok.