A mysterious young woman, Katie (Nicky Whelan), and her daughter move to a new town to escape her past and quickly befriends Angela Morgan (Gina Gershon), a mother of one who longs for a bigger family. As their lives become intricately entwined, Angela and her husband, Brian, (Nicolas Cage), invite Katie to live in their guest-house to serve as their nanny. Over time, the blossoming friendship between the two women spirals into a dangerous obsession as Katie becomes overly attached to the Morgans' daughter. Enduring lies and manipulations, Angela and Brian realize that sweet Katie is actually trying to destroy their family from within.

A psychological noir thriller set in 1960's New York based on Patricia Highsmith's novel, 'The Blunderer'. Walter Stackhouse is rich, successful and unhappily married to the beautiful but damaged Clara. His desire to be free of her feeds his obsession with Kimmel, a man suspected of brutally murdering his own wife. But when Clara is found dead in suspicious circumstances, Walter's string of lies and his own guilty thoughts seem enough to condemn him. As his life becomes dangerously entwined with Kimmel's, a ruthless cop is increasingly convinced he has found a copycat killer in Walter and aims to nail both murderers.