Sonic, Tails and Knuckles are walking across a bridge in Future City, searching once again for the Chaos Emeralds, when Tails' radar goes off. At that point, three mysterious riders on hoverboards smash through a nearby sign, and drop into the highway below. The trio realize that the Emerald's signal is coming from one of the three riders. Sonic begins pursuit on foot. He catches up with one of the riders, knocks him off his board, and hops on it. He quickly catches up with the lead rider, but is outmaneuvered. Sonic is thrown off his board, and the three mysterious riders disappears into the distance. The next day, Sonic's arch-nemesis, Doctor Eggman, appears on a giant screen in the city, and announces to the public that he is holding the EX World Grand Prix, in which racers will compete on Extreme Gear (the hoverboards used by the three previously encountered riders) to claim the title of champion. He also states that all entrants must pay a fee of one Chaos Emerald, and that "the winner takes all!" It is unclear whether or not he means that the winner will receive all seven Emeralds or not. Three racers are shown on the screen, and Sonic recognized them as the three mysterious riders they had encountered the night before. They are later discovered to be a group of outlaws, called "The Babylon Rogues".