In 1946 London, the Right Sort Marriage Bureau is just beginning to take off and the proprietors, Miss Iris Sparks and Mrs. Gwendolyn Bainbridge, are in need of a bigger office. The ladies are contacted by Gwen's cousin, Lady Matheson, who discreetly informs them that Princess Elizabeth has developed feelings for a dashing Greek prince, but now a blackmail note has arrived, alluding to some potentially damaging information about said prince. Iris and Gwen are asked to find out what secrets lurk in the prince's past, before his engagement to the future Queen of England is announced, and in this follow-up to The Right Sort of Man, the integrity of the Empire is at stake.