Earth is thrust into danger when a new menace arrives in the form of giant robots capable of hiding in plain sight! Of course Cobra is involved, but this time they aren't the biggest problem–not by a long shot. If the Joes are going to have a chance to save the planet, they’ll need equally big allies to face this new threat! In this special Transformers crossover expansion, the Joes will roll out with new Autobot friends like Bumblebee and Optimus Prime as they take on the evil Decepticons and their sinister Cobra cronies, led by Old Snake! Features: G.I. JOE teams up with the Autobots! A new crossover Mission with Space Bridge tile! New Autobot cards to recruit as allies! They can go on missions in their bot mode without requiring transport, OR in their alt vehicle mode where they'll be able to haul members of the JOE team along. New Ark component and Energon dice pool that must be managed to fuel Autobot skills and tech. Constructicons make cards more expensive to recruit, and if 6 are ever in play simultaneously, you'll have to take on the mighty Devastator! And more! —description from the publisher