At loose ends after the devastating death of her mother, Una Richardson responds to an advertisement for a ladies' companion, a position that leads her into the wealthy, secluded world of Mrs. Elspeth McKenzie. But Elspeth's home isn't the comforting haven it seems. Kathryn, her cold and bitter daughter, resents Una's presence. More disturbing is evidence suggesting two girls lived here before her. What happened to the young women? Why won't the McKenzie's talk about them? What are they hiding? As the walls begin to close in around her, Una fears she'll end up just like the other girls...