Walter Mitty, a daydreaming writer with an overprotective mother, likes to imagine that he is a hero who experiences fantastic adventures. His dream becomes reality when he accidentally meets a mysterious woman who hands him a little black book. According to her, it contains the locations of the Dutch crown jewels hidden since World War II. Soon, Mitty finds himself in the middle of a confusing conspiracy, where he has difficulty differentiating between fact and fiction.
A group of academics have spent years shut up in a house working on the definitive encyclopedia. When one of them discovers that his entry on slang is hopelessly outdated, he ventures into the wide world to learn about the evolving language. Here he meets Sugarpuss O’Shea, a nightclub singer, who’s on top of all the slang—and, it just so happens, needs a place to stay.