After settling in Environment-friendly Hills, Sonic is eager to verify he has what it requires a real hero. His test comes when Dr. Robotnik returns, this time around with a new partner, Knuckles, in search for an emerald that has the power to ruin worlds. Sonic partner with his own partner, Tails, and also with each other they start a globe-trotting trip to locate the emerald green prior to it comes under the wrong hands.