A hidden project developed 50 years ago has been released. Sonic is arrested after being falsely accused of crimes committed by The Ultimate Life-Form created Eggman’s grandfather Professor Gerald Robotnik and another but mysterious hedgehog, Shadow the Hedgehog joins the Eggman Empire seeking revenge on humanity for what they've done in the past and conquer the earth once and for all. This might as well be his deadliest plot yet. Meanwhile, Eggman threatens to destroy the world in 24 hours with a planet destroying weapon if the world doesn't surrender to his rule. Sonic and his friends investigate sightings of a mysterious hedgehog until they finally see that the hedgehog they're looking for is actually Shadow himself. In their adventure, they'll encounter an ultimate life-form reject called the Biolizard, find the Chaos Emeralds, all are efforts to stop Eggman from opening the all-powerful eclipse cannon on the Space Colony Ark. Sonic and his friends must team up with Shadow along with Rouge collect the seven Chaos Emeralds and stop the countdown before the world is destroyed.
