Summer Pitt is a fictional character, the daughter of Dirk Pitt from the Dirk Pitt series of adventure novels written by Clive Cussler. She and her twin brother, Dirk Pitt, Jr. were raised by their mother, Summer Moran, without Dirk Pitt's knowledge. Upon reaching adulthood, and following their mother's death, they united with Dirk Pitt. Both she and her brother currently work as researchers for NUMA. Despite being twins with her brother, she looks exactly like her mother, 6 feet tall and having flaming red hair and pearl grey eyes. In Treasure of Khan, Summer is kidnapped on a diving expedition and later escapes with the help of her brother. Along with her brother and dad, they discover a secret under-water cave.