Just when Andrew and Sandra Chillings think they can settle into a blissful marriage, Karen Chuckles enters their lives, pretending to be the perfect tenant for their rental property. Sandra, taken in by Karen's innocence, goes against her husband's wishes and offers Karen support even though their new tenant does everything to keep her at an emotional distance. No one really knows Karen's history except Mary Ann Peters, her one true friend. However, something is strange about their relationship, and Andrew Chillings is determined to expose it. Sandra feels her husband is too hard on their shy tenant and attempts to protect her from his scrutiny. Karen takes advantage of the situation and concocts a web of lies that shakes the foundation of the Chillings' marriage. Her fabrications not only entrap the Chillings, but anyone who attempts to play the "Good Samaritan."