Hitting the wheel at the start of the mission eventually activates a tile bridge. The tiles at the start of the bridge soon disappear, and a new section of tiles takes its place. The tiles eventually lead to a Blue Orb Fragment. There are two Mephisto that are intent on making things difficult for you, as they'll constantly poke and prod in an attempt to knock you off.
There is a trick to complete this mission quickly as Nero; the Red Queen Calibur skill and the Enemy Hike and Air Hike abilities are needed to pull it off. Slash the wheel to trigger the tiles, run to the end of the first two tiles that appear and jump straight ahead, use Calibur, Enemy Hike off of the Mephisto there and then Air Hike onto the ledge where the fragment is. You may need to straighten out the camera so to see where you're jumping. This video is from our unofficial game guide. You can view the full guide here