With the sequel raising the stakes for the titular hero, Sonic the Hedgehog 3 will also explore a wild new setting. The third installment in the movie franchise based on the SEGA games will see Sonic, Tails and Knuckles reluctantly partnering up with Robotnik in order to stop Shadow the Hedgehog amid his quest for destruction to get justice for his dark past. Ben Schwartz and Jim Carrey return to lead the ensemble Sonic the Hedgehog 3 cast alongside fellow franchise vets James Marsden, Idris Elba, Colleen O’Shaughnessey, Tika Sumpter and the introduction of Keanu Reeves as Shadow, among others.

https://screenrant.com/sonic-the-hedgehog-3-story-update-new-setting/