"The Cousins" is a young adult novel by Karen M. McManus that follows the story of three cousins, Milly, Aubrey, and Jonah, who are invited to spend the summer at their estranged grandmother's island resort. The invitation is unexpected, as their grandmother cut off contact with their parents years ago. The cousins are curious about their family's past and the secrets that may lie within. As they explore the island and their family's history, the cousins uncover dark truths and hidden motives. The story weaves themes of family, betrayal, and the quest for identity, keeping readers engaged with its suspenseful twists and turns.