Sonic the Hedgehog, Vol. 2

You are cordially invited to the celebration of a lifetime- The Knothole Victory Party! The victory celebration begins! Let the festivities get underway! Now that Robotnik has been defeated, everyone can feel safe and secure... or can they? Sonic doesn't seem to think so when everyone he knows and loves and is near and dear to him gets roboticized by a hidden enemy. What does this mean? Who's behind this latest attack? Is Dr. Robotnik really gone or has someone else taken over?