Up till now, the Autobots have had at least one safe haven on the world they found themselves stranded upon. Hated and shunned by the people they seek to protect, attacked by Decepticons and humans alike, the lot of an Autobot is not a happy one. But what they did have; what sustained them through their darkest hours (beyond the spirit of comradeship within the Autobot ranks) was their home from home - the crippled spacecraft known as The Ark! But now it seems that even the Ark has turned against them - or rather been turned against them! With most of the Autobots away attending the funeral of their leader, Optimus Prime, and only Ratchet remaining behind, the Ark is vulnerable to invasion. But it's not the Decepticons who are doing the invading! A lone human has dared to boldly go where no human has gone before (at least, not without a very specific invitation). The Ark is in the hands of the criminal known only as The Mechanic, and if Ratchet can't find a way to defeat him, Optimus Prime won't be the only Autobot going to meet his maker!