In a London slowly recovering from World War II, two very different women join forces to launch a business venture in the heart of Mayfair—The Right Sort Marriage Bureau. Quick-witted and impulsive Miss Iris Sparks and the practically minded widow Mrs. Gwendolyn Bainbridge find their venture off to a rough start when their newest client is found murdered and the man arrested for the crime is the prospective husband they matched her with. While the police are convinced they have their man, Miss Sparks and Mrs. Bainbridge are not. To clear his name—and to rescue their fledgling operation's reputation—Sparks and Bainbridge embark on their first investigation, but little do they know that this will put their very lives at risk.