Synopsis
Abigail Clayton (Selma Blair) lives alone. Very Alone. In fact, the attractive heiress has not left her Manhattan loft apartment for almost tow decades. The famous daughter of a wealthy industrialist, Abigail disappeared from the prying eyes of the press and the intrusiveness of her family on her 18th birthday, the day she received her massive inheritance. During years of self-imposed isolation, Abigail has had contact with only tow people, her building's concierge, Klandermann (Kevin Pollak), with whom she communicates via notes and Dr. Raymond Fontaine (Beau Bridges), a longtime family friend and her sole confidant for most of her life.

When the death of her elderly neighbor prompts NYPD Homicide Detective Frank Giardello (Giovanni Ribisi) to launch an investigation, Abigail is distressed to find him outside her door, asking to question her. Having tried to acquire the dead woman's now vacant apartment to ensure her privacy. Abigail is further upset when her requests go unanswered, and new tenants Lillian (Amy Smart) and Charlie (Jason Lee) move in.

Abigail anxiously monitors her new neighbors from the safety or her front door's peephole, but her well-ordered world begin to unravel when she finally encounters Lillian and Charlie face-to-face and her sheltered exitence becomes threatened in unexpected and terrifying ways.