Fighting Fantasy - City of Thieves - Rules of Play says:
PART STORY, PART GAME - PURE ADVENTURE! Are YOU brave enough to walk the dangerous, dark alleyways of Port Blacksand.? You must travel to the dark tower of demonic sorcerer Zanbar Bone, to put an end to his reign of terror. But you'll have to make it past the bloodthirsty thieves and creeping creatures of the night who lurk in Port Blacksand first. step up, hero, it's time to fight!