The storyline picks up shortly after the end of Sonic the Hedgehog 2: Dr. Robotnik's[1] space station, the Death Egg, has fallen out of orbit after his mech suit exploded in his final showdown with Sonic, causing critical damage to the ship.

However, instead of impacting the planet, the Death Egg crash-landed on Angel Island[2][3], a mystical floating landmass previously believed to exist only in legend. As Dr. Robotnik repairs the ship he meets up with the Island’s sole inhabitant, Knuckles the Echidna. Knuckles is the last surviving member of an ancient civilization, whose ruins and relics are scattered throughout the island. He is also the guardian of a set of Chaos Emeralds, which are the source of the island’s levitation powers.

Knowing Sonic and Tails will try to track him down, and realizing he can use the Chaos Emeralds to power the ship, Robotnik deceives Knuckles into believing Sonic is trying to steal his emeralds, and he’s come to help him. Shortly after, Super Sonic and Miles “Tailsâ€