Story: "A mysterious land mass called 'Onyx Island' suddenly appears in the south seas as if out of nowhere... The super-fast blue hedgehog, Sonic, and his best buddy Tails head off to search for clues as to what might have transpired.

'This has gotta be another one of Eggman's schemes!'

Sonic's hunch proves to be correct. As soon as they arrive at the island, they spot Dr. Eggman already waiting for them. As Sonic confronts Eggman, he triumphantly holds up a card. Sonic and Tails are shocked to see that the cards bears a picture of their friend, Amy Rose.

'Do you know what this is, Sonic?'

'I've sealed that little brat away inside this card!'

'Ha! Do you really think we'll believe that?'

While Sonic simply brushes off Eggman's supposedly ridiculous story, the more scientifically-minded Tails takes things more seriously.

'It might not be all that easy to believe, but it could possible for matter to be broken down at the atomic level and stored as digital card media...'

As Tails' quavering voice reaches Sonic's ears, there is a sudden blinding flash, as when it fades, Tails is gone. In Eggman's hand is a new card bearing Tails' image. Sonic stares in panicked disbelief. Then, who should appear but Knuckles, Sonic's more 'physically assertive' friend.

'Eggman!' you're behind the disappearance of the Master Emerald, aren't you?!' Knuckles says.

'Indeed!'

Eggman smiles, drawing from his bag another card, emblazed with the Master Emerald.

'Soon, everything in this world will be nothing more than another entry in my lovely card collection! If you think you can take your precious things back, then just you try it! Ha ha ha ha ha!'

After issuing his challenge, Eggman takes off and flies away.

Sonic and Knuckles vow to take him up on that challenge in order to take back what is in those cards.

'Sorry, Sonic, but this concerns the Master Emerald. This time I'M going in first!'

'Okay, Knuckles! Let's just see which one of us gets there first!'

At the same time, the mysterious black hedgehog, Shadow, arrives on Onyx Island, along with Silver, a guardian from the future, both seeking Eggman's cards.

Who will be the one to get the cards back from Eggman first? What is Eggman's true purpose in baiting these four to compete?"


Unlock Metal Sonic
To unlock Metal Sonic you must complete the game with Sonic, Knuckles, Silver, and Shadow.

Unlockable Cups	How to Unlock
Blue Chaos Cup	Complete every challenge in Death Yard Zone.
Cyan Chaos Cup	Complete every challenge in Colosseum Highway Zone.
Green Chaos Cup	Complete every challenge in Forest Falls Zone.
Grey Chaos Cup	Complete every challenge in the game.
Purple Chaos Cup	Complete every challenge in Meteor Base Zone.
Red Chaos Cup	Complete every challenge in Sky Park Zone.
Yellow Chaos Cup	Complete every challenge in Crystal Mountain Zone.

Unlockable Skins	How to Unlock
Knuckles	Complete story mode with Knuckles.
Metal Sonic	Unlock Metal Sonic
Shadow	Complete story mode with Shadow.
Silver	Complete story mode with Silver.
Sonic	Complete story mode with Sonic.