During the summer of 1983, Elaine and her daughters Hannah and Daisy move into Sunset Terrace, a squalid, low-rent apartment building in Los Angeles that houses single mothers. They have been on the road for three years, moving from town to town in a flight from tragedy ever since Hannah discovered her father dead in his study.


While Elaine struggles to make ends meet and construct a new life for herself in California, Hannah - a shy, lonely girl whose only companion in the shuffle of schools has been her pet turtle - develops an earnest affection for Bridget, a vivacious, foul-mouthed nine-year-old in apartment one who was abandoned as an infant in a supermarket parking lot. Now living with a foster family, Bridget quickly becomes Hannah's best friend, teaching her how to climb a chain-link fence and steal candy.


As the summer wears on, Elaine becomes captivated by Bridget as well, encouraging her to come over for dinner and sleepovers, taking on the role of a surrogate mother. Compelled by pity for the wayward girl, Elaine is blind to Bridget's dangerous influence on Hannah, who at the summer's end takes part in a malicious game that irrevocably alters the course of all of their lives.