Ann Stilwell arrives in New York City, hoping to spend her summer working at the Metropolitan Museum of Art. Instead, she is assigned to The Cloisters, a gothic museum and garden renowned for its collection of medieval and Renaissance art. Drawn into a small circle of charismatic but enigmatic researchers, Ann happy to indulge some of their more outlandish theories, including the museum's curator who is fixated on tarot and the real possibility of predicting the future.

But when Ann discovers a mysterious, once-thought lost deck of 15th-century Italian tarot cards she finds herself at the centre of a dangerous game of power, toxic friendship and ambition. And as the game being played within the Cloisters spirals out of control, Ann must decide who she trusts.