Prince Horace can be annoying and craving attention from his father, he frequently misbehaves—to the point he is nicknamed "Prince Brat." Since he is a prince, no one may raise a hand against him. Therefore, his family provides him with a whipping boy, Jemmy, an orphaned boy who will be punished in the prince's stead. Though he has learned to read, write and do mathematics while living in the castle, Jemmy is beaten several times a day and longs for the freedom he had on the streets. When the prince decides to run away on a whim, he demands that Jemmy act as his servant during his journey. While on the run, the boys are picked up by two notorious highwaymen, Hold-Your-Nose Billy and Cutwater, who hatch a scheme to ransom the prince. Jemmy talks them into believing that he is the prince, and sets into motion a plan of escape. The prince misunderstands Jemmy's intentions and betrays him. Nonetheless, the boys escape. They come across a girl named Betsy searching for her lost dancing bear, Petunia, and she directs them to the river where they find a kind man with a wagon full of potatoes. The boys help the man - whose name is Captain Nips - get his wagon out from the mud, and in return, the potato man gives the boys, the girl, and the bear a lift to the fair, but they are soon intercepted by the highwaymen. Still believing Jemmy is the prince, and believing it to be a crime worse than murder to beat the prince, they beat Horace instead. Petunia scares the highwaymen away, and everyone arrives at the fair. Betsy earns a few coins with her bear, Captain Nips boils the potatoes and sells them, and Horace and Jemmy head down to the sewer to catch some rats. On their way, they hear some people talking about the missing prince - one woman makes a remark about how much worse things will be when the prince becomes king. Horace's feelings are hurt very deeply, but he does not show his emotions. When the boys learn that the king has posted a reward for the whipping boy, who has been accused of kidnapping the prince, they go into the sewers where they see the highwaymen. They trick the highwaymen into the most dangerous sewer, where rats attack them. Afterward, the prince decides that he wants to finally go home. When they return to Captain Nips, Horace reveals himself as a prince and suggests that the potato man collect the reward for capturing the whipping boy. Although Horace tries to explain the entire escapade to the king, Jemmy is ultimately pardoned, and the prince and Jemmy live happily ever after as the best of friends in the castle. Hold-Your-Nose Billy and Cutwater eventually escape the sewers, but mistakenly board a ship that goes to a prison island.
Characters
Jemmy – the whipping boy, formerly self-employed as a rat catcher. Sometimes thinks of Prince Brat as a friend.
Prince Horace – heir to the throne, also known as Prince Brat. Prankster; runs away with Jemmy
Hold-Your-Nose Billy – notorious highwayman who stinks like garlic. He and Cutwater stow away on a ship which turns out to be heading to a prison, concluding the book.
Cutwater – highwayman and partner of Hold-Your-Nose Billy.
Betsy –a fourteen-year-old girl with a dancing bear named Petunia.
Captain Nips – a near-sighted old man who sells potatoes.
King – The king-Prince brat's father. At the end of the book, is shown to have a sense of humor.
Petunia – Betsy's dancing grizzly bear. She is considered cute and cuddly.
Film adaptation
Fleischman's book was adapted in the 1994 television filmThe Whipping Boy, starring George C. Scott and directed by Sydney Macartney. Sid Fleischman wrote the teleplay and the film won the CableACE Award that year.
Musical adaptation
As of 2016, a musical adaptation was reported to be in the works with music by Drew Gasparini and book by Alex Brightman, with both contributing to lyrics.