When upbeat, outgoing Karen, her husband Scott and their young son relocate to Washington for Scott’s job, Karen looks forward to starting a new life. She soon meets Lisa, her beautiful charming neighbour and they quickly bond. Lisa soon starts lying to Karen, and about Karen to others. Lisa cleverly sets herself up as Karen’s victim, until every aspect of Karen’s new life starts to unravel. Karen doesn’t realise how desperate and cunning Lisa is—until things come to a shocking head.