Based on the Pulitzer Prize-winning play by David Auburn, "Proof" follows a devoted daughter (Paltrow) who comes to terms with the death of her father (Hopkins) - a brilliant mathematician whose genius was crippled by mental instanity - and is forced to face her own long-harbored fears and emotions. She adjusts to his death with the help of one of her father's former mathematical students (Gyllenhaal) who searches through her father's notebooks in the hope of discovering a bit of his old brilliance. While coming to terms with the possibility that his genius, which she was inherited, may come at a painful price, her estranged sister (Davis) arrives to help settle their father's affairs.
PROOF is the compelling story of an enigmatic young woman haunted by her father’s past and the shadow of her own future, exploring the links between genius and madness, the tender relationships between fathers and daughters and the nature of truth and family.
On the eve of her twenty-seventh birthday, Catherine (Paltrow), a young woman who has spent years caring for her brilliant but unstable father, a mathematical genius named Robert (Hopkins), must deal not only with the arrival of her estranged sister, Claire (Davis), but also with the attentions of Hal (Gyllenhaal), a former student of her father’s who hopes to find valuable work in the 103 notebooks of Robert’s.
As Catherine confronts Hal’s affections and Claire’s overbearing plans for her life, she struggles to solve the most perplexing problem of all: How much of her father’s madness – or genius – will she inherit?