Compelling drama about an enigmatic young woman haunted by her father's past and the shadow of her own future. On the eve of her 27th birthday, Catherine (Gwyneth Paltrow), a young woman who has spent years caring for her brilliant but unstable father, a mathematical genius named Robert (Anthony Hopkins), must deal not only with the arrival of her estranged sister, Claire (Hope Davis), but also with the attentions of Hal (Jake Gyllenhaal), a former student of her father's who hopes to find valuable work in the 103 notebooks of Robert's.