When Alison (Bridget Fonda) discovers her fiancé, Sam’s infidelity and kicks him out of her Manhattan apartment, she advertises for a “single white female” roommate to share the costs. After some strange and unsuitable applicants are rejected, along comes Hedra (Jennifer Jason Leigh), a seemingly quiet and respectable roommate. Things begin well and the two get on famously until Alison begins noticing small incidents that just don’t add up. Hedra seems intent on becoming more and more like Alison and begins to get controlling. After the strange behavior persists, including the unexplained death of their puppy, Alison confides in her neighbor, Graham who takes an interest. The re-entry of Alison’s fiancé exacerbates matters further. It soon becomes apparent that Hedra is troubled by a traumatic past and is less than the emotionally stable and quiet roommate she first appeared to be. As she becomes increasingly hostile, the tension builds until there is a dramatic and climatic confrontation between the two. Based on a novel by John Lutz.