A large, grassy canyon containing the ruins of an old castle. It borrows visuals of Lost World from Sonic Adventure. The Mach Speed Zone for this level is a speedy dash including running along walls of water. Sonic and Shadow have been seen riding an eagle on this level. It is the level playable in all of the demo builds of the game so far, including the Xbox Live Marketplace demo. This action stage also seems to be a darker version of the "Green Hill" zone from Sonic the Hedgehog for some of the background visuals, like the water falls and the canyons that resemble the "Green Hill's" background.
- Sonic's Story (8th Stage)
- Although this is the first level announced and the first publicly playable level for Sonic, this is actually the penultimate stage for him. Sonic journeys to the ancient castle in search of Dr. Eggman, who has captured Princess Elise yet again and hopes to collect the Chaos Emerald hidden there.
- Shadow's Story (2nd Stage)
- Shadow escorts Rouge to the castle of Soleanna in Kingdom Valley, with the Scepter of Darkness in tow.
- Silver's Story (8th Stage)
- Realizing that the princess holds Iblis inside her, Silver rushes through this stage to find and save her.