Sonic settles in Green Hills, seeking more freedom. Tom and Maddie agree to leave him home while they go on vacation. However, Dr. Robotnik returns, this time with Knuckles, in search of an emerald with the power to build and destroy civilizations.

Sonic the Hedgehog 2
Sonic and Tails must band together to stop the unlikely alliance of Dr. Robotnik and Knuckles, who threaten to destroy the safety of their home, Earth.