In Karen M. McManus's gripping standalone thriller, 'The Cousins,' four estranged cousins—Milly, Aubrey, Jonah, and their mysterious relative Archer—are invited to spend the summer working at their wealthy grandmother's luxury island resort. The catch? Their grandmother, Mildred Story, disinherited their parents years ago, sending a chilling one-line letter: 'You know what you did.' As the cousins uncover the dark history of the Story family and their grandmother's true intentions, they realize that secrets, lies, and danger lurk beneath the island's pristine surface. McManus masterfully weaves a complex web of suspense, exploring themes of family loyalty, betrayal, and the shocking truth behind a long-held secret. This is a must-read for fans of psychological thrillers with unexpected twists.