After Sonic the Hedgehog sacrificed his own life to save the world in the aftermath of a crisis which brought Zootopia to his homeworld of Mobius, Sonic, alive but trapped in time, is found by longtime friend and rival Shadow the Hedgehog, who brings him back to Mobius to stop the greatest threat he's ever known. And as Mobians and Zootopians reunite, can they save their future?

After an unauthorized experiment brings the city of Zootopia to Sonic's world, Sonic and Tails are tasked to return Zootopia to the proper universe once more. Only one problem- Sonic finds he can't stop thinking about the bunny who asked him. But when an old enemy returns and a paranormal threat appears, can Mobius- and Sonic- survive?