It's endgame, as Sonic and Infinite face off for the final time. Just as the Phantom Ruby reaches full power, the rookie intervenes and helps Sonic turn the tide of the battle. With Infinite defeated, the resistance presses their advantage, with Classic Sonic leading the charge through the Iron Fortress while the rookie and Sonic reach the main reactor. With the main tower destroyed, it appears as though the resistance has won, but Eggman has one final trump card up his sleeve. A new and improved Death Egg Robot, powered by the Phantom Ruby, is unleashed upon the resistance but the heroes unite to take on this final robotic nightmare...