Dr. Eggman has traveled to the mystical Angel Island in search of the all-powerful Master Emerald and the legendary seven Chaos Emeralds, and he has the mighty guardian of the Master Emerald and last of the echidna tribe, Knuckles the Echidna tricked into helping him but he invent his other ultimate creation: a second but much stronger, faster, more powerful robot duplicate of Sonic called Mecha Sonic. Sonic, Tails, Sonic’s now girlfriend Amy, Cream and Cheese, Sally and the rest of his team of Freedom Fighters land on the mysterious and mystical Angel Island, floating in the sky to search for a greater magic that holds the balance of the world. They are intercepted and find themselves outmatched by Knuckles who thinks they've come to steal the Master Emerald. Sonic duels with Knuckles while the real menace, Eggman steals the Master Emerald to fuel his greatest creation, The Death Egg. Until Eggman betrays Knuckles as he learns the truth then teams up with Sonic whom he became best friends with and became a part of the team and his friends to stop him and Mecha Sonic once and for all from getting his hands on the Master Emerald while Sonic becomes super by using the chaos emeralds.
