Without the consent of the King, Sonic and the Freedom Fighters infiltrate the center of the Eggman Empire deep in the technological monstrosity of Megaopolis. However, they are not there to take down Robotnik's latest scheme, but rather to save a friend.
Synopsis: The popular "Mobius, 25 Years later" saga continues! King Sonic, Queen Sally and their kids make the journey to visit Knuckles, Julie-Su and Lara-Su on Angel Island... but some of them are not happy with it! Is there trouble in paradise?