From the window of her New York apartment, lonely housewife Diane Arbus (Kidman) locks eyes with a masked figure on the street - a mysterious new neighbour (Downey, Jr.). Drawn to the man who intrigues her and determined to take his photograph, Diane ventures to his apartment and embarks on a journey that will unlock her deepest secrets and awaken her remarkable artistic genius, launching Diane on her path to becoming the artist she is meant to be.