Thief: Deadly Shadows might lack a "3" in its moniker, but don't be fooled. The game picks up right from where Metal Age left off. Near the end of that game, Garrett was universally against anything beyond saving his own ass, and therefore ignored the prophecies that told him of a great darkness coming. His selfishness ended up killing his partner in crime. So, in the epilogue, Garrett accepts his fate as being something of a world-saver, and he agrees to help with the prophecy.