On the moon, the Mini-Cons discover a stronghold, built and maintained by their own kind, hidden for over one million years. But is it a sanctuary... or a prison? Either way, the previously Earthbound Mini-Cons are now in residence, and not everyone's happy to be there! Oh, and the Decepticons want their Mini-Cons back! New characters, new revelations, and the same old high-octane action and excitement!