Shadow finds out that Eggman fooled him by making a mash-up video of Sonic saying mean things about him. Meanwhile, Eggman finds out that Shadow is after him, so he hides out in another dimension. But suddenly, Sonic and Shadow find him, and another Eggman is in their dimension. And suddenly, a world collision happens. It's up to Sonic and his friends to find the Eggmans and save the world.