Quick recap
In 1974, the alien hedgehog Shadow is held by G.U.N. and befriends Maria, granddaughter of scientist Gerald Robotnik. When Maria dies in an explosion, Shadow is put in suspended animation. In 2024, someone frees him. G.U.N. calls in Sonic, Tails and Knuckles, now Team Sonic. They find that the one who freed him is Gerald himself, who plans to fire the orbital Eclipse Cannon with help from his grandson Ivo Robotnik. Sonic loses control, steals the Master Emerald and fights Shadow, until he tells him about losing Longclaw. Shadow switches sides. In the end, Ivo and Shadow steer the cannon away from Earth and sacrifice themselves, and Sonic meets Amy Rose and an army of Metal Sonics.

