An antique dealers revelation about a former queens priceless heirloom starts Nancy on a trail of exciting adventures. Madame Alexandra, now living incognito in River Heights, asks Nancy to find her missing grandson. With only one clue to go on a faded photograph of the prince at the age of four the young detective begins her search. Nancys investigation unmasks a slick imposter and reunites the long-separated family in this suspense-filled story.