"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. The Thief Lord, whose real name is Scipio, takes the siblings on adventures while they uncover secrets about a magical carousel that can turn children into adults. The novel explores themes of family, friendship, and the importance of staying true to oneself amidst challenges.