Sonic Knuckles and Tails are walking across a bridge in the city, searching 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 his feet. 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 a 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 he 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". Sonic responds "Let's do this!" with his usual enthusiasm, and the three set off to join the race.

The Babylon Guardian (called Angelus the Gatekeeper in Japan) is a genie in a bottle, and resembles a large purple hawk who guards the treasure of Babylon. The treasure he was protecting was revealed to be a "magic carpet" which was actually a prototype Extreme Gear created by the ancient Babylonians. He regards those who seek treasure as greedy, and he is hidden behind a large door in Babylon Garden (the Hanging Gardens of Babylon in Japan). He is the final and only "boss" of Sonic Riders. He is defeated by Sonic at the end of the Babylon Story. He was voiced by Madeleine Blaustein in English.

 Gameplay

The game is played in its entirety using hoverboards. Players must race seven other competitors on a total of 14 tracks, 9 of which must be unlocked through progress in the story mode. Each individual character has different statisitics, altering their performance slightly in races. A key component of the game is the air tank, displayed in the lower right-hand corner of the screen. Air serves as the fuel for Extreme Gear, and is depleted gradually as the race goes on. It is also depleted faster by certain maneuvers. These include cornering, which involves using the air as a sideways force against the board, allowing the player to round sharp turns with ease, and building tension before a jump, which involves using the air to propel the player higher off of ramps. After going off ramps, players can perform various tricks, which refill the air gauge according to their rating. Building the tension before a jump will allow the player to perform more tricks before landing. Thorughout the courses, there are many rings lying about. Picking them will allow the player to reach higher performance levels. Players start races at Level 1 withno rings and max out at level 3, with 60-100 rings. Possibly the most costly maneuver in terms of air is boosting, by which a player greatly increases speed for a short duration. If a boost is performed when in close range of an enemy racer, the player will launch an attck against the racer, causing them to lose rings, and remain stunned for a short duration.

Rider Attributes Each racer in the game has one of three beneficial attributes: Speed, Flight, and Power. Their abilities are as follows: Speed- Allows players to grind along rails. Flight- Allows players to propel themselves in mid-air through a series of suspended hoops. Power: Allows players to bash certain obstacles out of their way. Each of these maneuvers will refill the air gauge partially when used.

Gameplay Modes Story Mode: Players take part in consecutive races, one after the other, based on the storyline, in order to defeat the Babylon Rogues and win the Grand Prix. Throughout the story, Sonic, Tails and Knuckles must each challenge and defeat the respective member of the Babylon Rogues that matches their attribute type.

Mission Mode: Only unlocked after successfully completing the original story. Players take part in various missions assigned in order to gain secret gears.

Survival Mode: A special mode of gameplay consisting of two separate modes: race and battle. Race consists of snagging a Chaos Emerald on the track, and passing through five hoops without having the Emerald stolen by another racer. The Emerald is stolen by attacking the player holding it. Battle involves launching attacks at the three other racers on the track. Each racer begins with three health points. The racer loses a health point every time they are attacked. The last racer standing wins the match.

Shop: Players can purchase new Extreme Gear with the rings collected in previous races.

Types of Gear There are three types of gear in the game: Boards, the gear unlocked initially, and the only gear used in story mode. Skates, which tend have slightly lower performance than boards, but burn less air, and bikes, which resemble floating mopeds, and have higher performance, but burn more air. Most gear must be purchased from the shop or unlocked in story mode.

Alternate Story After the initial story is completed, another story is unlocked, in which players assume the role of the Babylon Rogues in their quest to find hidden treasures. The levels in this story are, altered, more difficult versions of the original tracks, and are unlocked by completing this story. After both story modes are completed, a selection of new characters not featured in the story become playable. At the end of this alternate story, players battle the only boss in the game.