Optimus Prime was supposed to have led the Autobots to victory. Instead, the fate of Cybertron is unknown, and his allies have crash-landed far from home, alongside their enemies - the Decepticons. As these titanic forces renew their war on Earth, one thing is immediately clear: the planet will never be the same. New alliances are struck. Battle lines are redrawn. And humanity's only hope of survival is Optimus Prime.