"Two Can Keep a Secret" is a young adult mystery novel by Karen M. McManus. The story revolves around Ellery, a teenager who moves to the small town of Echo Ridge, where her twin brother, Ezra, and she uncover dark secrets related to a long-unsolved murder and the recent disappearance of a classmate. As Ellery navigates high school life, she discovers that the town has a history of secrets and lies. The narrative explores themes of trust, friendship, and the impact of the past on the present, ultimately revealing how closely intertwined the lives of the characters are.