Cooney has long been intrigued by the subject of familial loss and the messy, ungovernable feelings that are its emotional aftermath (The Face on the Milk Carton, 1990, etc.). In this new outing, an instantly gripping story about a girl deserted by her thieving parents, Cathy is confronted by a fellow summer-program student named Tommy, who loudly and publicly declares that she’s his missing cousin Murielle. He claims that her parents, high-living financial schemers, took the money and ran to Europe and that in the grisly aftermath, she was taken from his parents, her aunt and uncle, and put into foster care before disappearing into the system. Cathy can’t deny that she bears a strong resemblance to the missing girl, and the story develops legs. The FBI, which never lost interest in capturing the embezzling pair, wants to use Cathy to try and lure them back to the United States. As the fast-paced plot unfolds, it goes from an is-she-or-isn’t-she story to something emotionally richer, a tale about selfishness and self-sacrifice and the deep connectivity of familial ties. (Fiction. 12 & up)