Years after their long journey through Equestria, Sonic and his friends celebrate the heroic hedgehog's 25th birthday. It appears to be another normal day until a dimensional collision sends Sonic’s world and Equestria into chaos. Now, The Blue Blur must team up with the Mane 6 once again on an epic adventure to restore the Harmony Stones as well as their worlds. Only this time, Dr. Eggman is determined to defeat our heroes with the help of their most notorious foes…