After working out in Eco-friendly Hills, Sonic is eager to show he has what it requires a real hero. His test comes when Dr. Robotnik returns, this moment with a new companion, Knuckles, in search for an emerald that has the power to damage human beings. Sonic join his very own sidekick, Tails, and also together they start a globe-trotting journey to locate the emerald before it comes under the wrong hands.