Deadly Shadows (some spoilers)
In Thief III: Deadly Shadows, Garrett has finally been persuaded to cooperate with the Keepers after hearing that their prophecies might concern him. His friend Keeper Artemus asks him to steal two holy artifacts, one from the Pagans and one from the Hammerites, in order to hear what those prophecies are. But the prophecies speak of a betrayer who will destroy everything, and most of the Keepers suspect Garrett is that betrayer. Help comes from some unexpected quarters, but can Garrett's stealth prevail against the suspicion of his own allies and an immortal magician of immense power?