《你知道的魔鬼》讲述的是：　　Kathryn Vale (Lena Olin) is a reclusive ex-movie star with a dark secret and a daughter hoping to follow in her mother's movie-star footsteps. When Kathryn attempts to make a career comeback, she is threatened by an anonymous blackmailer. The resulting events force Kathryn to confront the truth about herself and those around her.