School is out in the summer of 1925 in Dayton, Tennessee. For Frances Robinson, a 15-year-old daydreamer with a crush on her teacher, John T. Scopes, summer vacation promises tennis and Coca-Colas from her father's drug store. But when Frances' father, the school board chairman, has Scopes arrested for teaching evolution, the sleepiest place on earth becomes a hotbed for famous thinkers, including H.L. Mencken, Clarence Darrow, and William Jennings Bryan.

Overnight, the world is flocking to Dayton to decide important questions: Are people really descended from monkeys? Does the theory of evolution have a place in biology class? As Frances sees the man she loves crumbling beside her, she begins to question her town, her neighbors, and the father she has always trusted.