When New York designer Beatrice gets a frantic call in the middle of Sunday lunch telling her that her younger sister, art student Tess, is missing, she boards the first flight home to London. But as she learns about the circumstances surrounding her sister's disappearance, she is stunned to discover how little she actually knows about her sister's life -- and how unprepared she is for the terrifying truths she must now face. Beatrice and Tess have exchanged long, intimate letters, and Sister is framed as a letter from Beatrice to Tess. The facts of Tess's disappearance and likely death are slowly revealed to the reader in a persuasive -- and memorable -- narrative.