The photos Judith Stanley takes are just for her, a private passion to fill her suburban days. But when she shares them with Paul Sorenson, her new photography instructor, she's unprepared to hear his astonished praise. Emboldened by Paul’s encouragement, Judith ventures out beyond her quiet neighborhood to the city in search of increasingly striking images. When she starts to notice the dark shape of a man in the corner of her self-portraits, Judith is certain he's an attacker from her past. She doesn't know why he has returned, but she's sure of his presence. Until one night when the man finally emerges from the shadows and Judith’s story suddenly and irrevocably becomes his own.

No one knows Margo’s real name. Her colleagues and patrons at a small-town public library know only her middle-aged normalcy, congeniality and charm. They have no reason to suspect that she is, in fact, a former nurse with a trail of premature deaths in her wake. She has turned a new page, so to speak, and the library is her sanctuary, a place to quell old urges. That is, at least, until Patricia, a recent graduate and failed novelist, joins the library staff. Patricia quickly notices Margo’s subtly sinister edge and watches her carefully. When a tragic incident in the library bathroom gives her a hint of Margo’s mysterious past, Patricia can’t resist digging deeper --- even as her new fixation becomes all-consuming and sends both women hurtling toward disaster.

Though the two women live just a few doors apart, a chasm lies between them. The actress, a celebrity with a charmed career, shares a gleaming brownstone with her handsome husband and three adorable children, while the recently separated narrator, unhappily childless and stuck in a dead-end job, lives in a run-down, three-story walk-up with her ex-husband’s cat. As her fascination grows, the narrator’s hold on reality begins to slip. Before long, she’s collecting cast-off items from the actress’s stoop and fantasizing about sleeping with the actress’s husband. After a disastrous interaction with the actress at the annual block party, what began as an innocent preoccupation turns into a stunning --- and irrevocable --- unraveling.