The Prince of Wales has asked four wealthy entrepreneurs and their wives to Buckingham Palace to discuss a fantastic idea: the construction of a six-thousand-mile railroad that would stretch the full length of Africa. But, alas, the prince's gathering proves disastrous when the mutilated body of a prostitute turns up in a linen closet among the queen's monogrammed sheets.
With great haste, Thomas Pitt, brilliant mainstay of Special Services, is summoned to resolve the crisis. The Pitts' cockney maid, Gracie, is also recruited to pose as a palace servant and listen in on the guests' conversations. If Pitt and Gracie fail to find out who brutally murdered the young woman, Pitt's career will be over, and the scandal may just cause the monarchy to fall.