Two months after Sonic, Tails, and Knuckles' adventure in Sonic Universe 1, Robotinik returns. He calls Shadow to help him, but Shadow doesn't accept because he lost badly two months ago... Robotinik doesn't like it and leaves. So Shadow turns good and tries to support Sonic & co. against Robotinik (again!!). Now Robotinik is back stronger than ever! He takes the Master Emerald and leaves! Help Sonic & Friends get the Master Emerald back!