Surprise House is a story about a family, the Corlisses, who inherit a mysterious old house from their eccentric great-aunt, Miss Nan Corliss. The house is filled with her strange collections, practical jokes, and hidden secrets. The adventure begins when Mary, the daughter, inherits the library – a room brimming with books and a portrait of Miss Nan herself. As Mary explores her new domain, she discovers a hidden watch, hinting at the many mysteries the house and her great-aunt have left behind. This unexpected inheritance sets the stage for the Corliss family to uncover the secrets of Surprise House, all while learning about their unique great-aunt and her intriguing past.