The Great Mouse Plot is an excerpt or short story taken directly from Roald Dahl's autobiography, Boy: Tales of Childhood, often published separately for events like World Book Day. The tale recounts one of the most famous anecdotes from Dahl's youth. It describes how the young Dahl and his friends, fed up with the cruel, unhygienic local sweet-shop owner, Mrs. Pratchett, decide to play a momentous prank on her. They sneak a dead mouse into a jar of her most tempting gobstoppers, resulting in chaos and swift, though painful, retribution. The story is a defining moment in Dahl's history, showcasing his early appreciation for a good, righteous prank against a horrible adult.