"The Thief Lord" is a children's fantasy novel written by Cornelia Funke. The story follows two brothers, Bo and Prospero, who run away from their aunt and uncle in Germany and find refuge in Venice. There, they meet a mysterious boy known as the Thief Lord, who leads a group of street children. As the plot unfolds, the children become involved in a magical adventure that includes a stolen magical artifact. The novel explores themes of friendship, family, and the importance of being true to oneself, all set against the enchanting backdrop of Venice.