POV Alexios Komnenos, ruler of New Constantinople, enters into an alliance with Mayor Richard J. Daley of Shytown against the community of Bornu, ruled by MuslimMusa ar-Rahman. Both rulers fear that they will turn on each other once Bornu is defeated. As set forth by Farmer's works, all of the characters are people who lived and died on Earth, but were resurrected with a physical age of 25 on Riverworld. This gives Turtledove the chance to introduce a Byzantine character, making use of his considerable knowledge of and affinity for that historical setting.
The title directly refers to Alexios and Daley; Daley declares that one horse thief (himself) can spot another (Alexios). In the end, Alexios proves the craftier thief.