With a storm raging against Angel Island, Sonic and his friends are in a fight for their lives! Trapped underground and separated from his friends, Sonic finds himself face-to-face with—wait—that's not Amy?As something terrifying happens beneath the ground, on the surface, Knuckles and Tails brave the violent storm ripping through Angel Island—although they have their own foe to deal with.Can our heroes persevere through the chaos and keep everyone safe? Or will these mysterious figures claim another emerald... or even a life?