Sonic is being held in a top security prison, Prison Island, thanks to Shadow and Eggman. Tails, Amy, Chris and Mr. Tanaka venture onto the island to save Sonic. Shadow, Eggman and Rouge venture onto Prison Island to retrieve three more Chaos Emeralds Shadow, Rouge and Chris arrive in the ARK. Eggman starts to get the Eclipse Cannon ready to destroy the Earth! Eggman begins test and destroys the half of the Moon. Sonic and co. arrive to stop Eggman from using the Eclipse Cannon to destroy the Earth. Tails gives Sonic a fake Yellow Chaos Emerald, thinking it will destroy the Cannon when placed in with the other Emeralds. As the Space Colony ARK heads for the Earth, the combatants put aside their differences to stop the descent. However, Shadow refuses to help since he believes mankind deserves to die because of what they've done. Chris attempts to reason with Shadow, only to be knocked away several times. Finally, he finally realizes Maria's true wish and decides to help.
Synopsis for this movie has been provided by The Movie Database.