During the sweltering summer of 1915, Pin, the 14-year-old daughter of a carnival fortune-teller, dresses as a boy and joins a gang that roams the famous Riverview amusement park, looking for trouble. But in this "well-crafted and deliciously unsettling period thriller" (Booklist), the park is also host to a killer hiding in the shadows of the carnival. When Pin sees a man enter the Hell Gate ride with a young girl and emerge alone, she knows that something horrific has occurred. The crime will lead her to the outsider artist Henry Darger, a man who is brilliant but seemingly insane. Together, the two navigate the seedy underbelly of a changing city to uncover a murderer few even know to look for.