Sonic Adventure DX: Director's Cut

Doctor Robotnik is hunting for a fresh way to crush his old rival Sonic and seize the world. His research turns up Chaos — a creature that, thousands of years ago, protected the Chao and the all-powerful Master Emerald, the gem that balances the seven Chaos Emeralds. Long ago, when a tribe of echidnas tried to seize the Emeralds' power and shattered their harmony with the Chao, Chaos struck back, channeling that power to become the monstrous Perfect Chaos and nearly wipe them out. Before it could destroy the world, a young echidna named Tikal, who had befriended Chaos, sealed it — and herself — inside the Master Emerald. Now Eggman frees Chaos, and Sonic and his friends must thwart his schemes and stop the creature from growing stronger still.