From Gamespot:
http://e3.gamespot.com/story/6265707/assassins-creed-driver-splinter-cel...
"Assassin's Creed: Lost Legacy sees Ezio travel east to the Assassins' lost castle in Masyaf, where he'll seek out the origin of his order, further connecting the events of the series. "
Now the premise sounds interesting, shame it'll only be for the new system.