The brief summary of the plot is a giant planet eating robot is zeroing in on Cybertron for no good reason other than to give a good bit of planet eating destruction. This is set against a backdrop of the Autobots beginning their final preparations to re-capture Cybertron from the Decepticons from Moon Base 1 and 2. During their last fuelling mission to Autobot City on Earth a very high number of Autobots (coinciding with their toy counterpart removal from production) bite the last ticket. Megatron then manages to use the shuttle to bypass Autobot security and launch a devastating assault that culminates in Optimus Primes final battle. The story then leads onwards and features the moon bases being eaten and the remaining Autobots get chased around the galaxy by a temporarily frustrated Decepticon army. The story culminates in a final battle at Cybertron where the goodies are eventually victorious and Rodimus Prime (the new leader of the Autobots) is born.
As a kid I remember the horrifying moment where some of my favourite Autobots were destroyed with such casual ease. Obviously I did not recognise the toy connection at that point but it sort of makes sense. To put the very high death toll into perspective about 12 robots were destroyed in the first 25 minutes!
Autobot deaths: (supplied by this Wikipedia article. Their deaths way outnumber the Decepticons therefore leading me to assume that the Decepticons were a more popular toy!
Optimus Prime
Huffer
Ironhide
Prowl
Ratchet
Brawn
Windcharger and
Wheeljack
I think that you can tell from the long winded review that I am going to award this one
PS I forgot to mention that I was involved with Mike Riley being listed in the writing / editing credits.

