Sonic the Hedgehog and his best friend Tails are hot on the trail of the villainous Doctor Eggman, who has captured a host of their animal friends to power his ever-growing robot army. During the pursuit, Eggman shoots down Tails' plane, and the two heroes crash-land in a strange new world floating in the sky known as the Lost Hex. As they explore this uncharted realm, they discover that Eggman has enlisted the aid of the Deadly Six, a group of the world's native Zeti creatures, keeping them obedient with a magical conch. When Sonic impulsively kicks the conch away, the Deadly Six turn against Eggman and seize control of his robotic forces, setting in motion a new and dangerous threat that forces old enemies into an uneasy alliance.