The Sisters' Royal Dilemma is sixth in the Home Office Lord's series and begins about a week after book three ends. The story follows sisters Lady Madeleine and Lady Olivia as they attempt to make their father's country house party the very best for all guests and find love along the way. One guest begets another, as a foreign dignitary is invited on behalf of the Queen. The two sisters have found their beaus, but which is whose? Lord Augustus Durant, Gus for short, also Viscount Pelham, is finally back in England after being off on his grand tour. He receives a note from an old schoolmate that sparks his interest as well as being somewhat cryptic. Only one way to find out the meaning behind it. Weeks later, he is invited to a house party put on by the Marquis of Worth; however, not long after arriving, Pelham is informed a friend from a foreign nation is in London, and he is being sent to retrieve him. Apparently, he is on a mission of his own, one that requires his presence at Worth Park. Once both men reach the sprawling country estate, Gus finds the rest of the original group from the Home Office. An impromptu meeting regarding the investigation of the Crowned Griffon Society offers nothing but an increasing list of possible aristocracy involved in the mysterious organization. What is next for our lords?