The quest for Energon – a rare and potent substance that the Autobot and Decepticon warriors have battled over for eons – continues on Earth! The Decepticon forces have struck a deal with Unicron: in exchange for new powers and forms, they will supply enough Energon to fully reactivate him. Now legions of hyper-powered Decepticons speed toward Earth, intent on controlling its Energon resources at any cost! Only and elite team of Autobots, empowered with the Sparko of Combination, can save the planet from total destruction.
Descriptions taken from AniDB.net