A woman struggles to come to terms with the potentially dangerous legacy of her late father in this drama based on the award-winning stage play by David Auburn. Catherine (Gwyneth Paltrow) is a woman in her late twenties who is strongly devoted to her father, Robert (Anthony Hopkins), a brilliant and well-known mathematician. While Robert's skill in the world of numbers still appears to be strong, his grip on reality begins to slip away, and as Robert descends into madness, Catherine begins to wonder if she may have inherited her father's mental illness along with his mathematical genius. After Robert's passing, Catherine is confronted by Hal (Jake Gyllenhaal), a gifted but zealous student of Robert's who wants to look through the late man's notes in hopes of finding his last great work. While Catherine is hesitant to look too deeply into her father's work for fear of what it might suggest about her own future, she allows Hal to do so, and when one notebook reveals a mathematical proof of potentially historic proportions, it sets off shock waves in more ways than one. Proof also stars Hope Davis as Catherine's well-meaning but shallow sister, who doubts Catherine's ability to take care of herself. Paltrow had previously played Catherine to stellar reviews during the original play's run in London's West End.