In this episode, the plot revolves around 'Beau,' who recently graduated from Cambridge along with his fellow graduates Moriarty and Grytpype-Thynne. They attend a ball at Oxley Towers, where Lady Seagoon's famous 'Blue Shower' diamond, worth a king's ransom, is stolen. By the time the police arrive, 'Beau' has decided to join the Foreign Legion. He faces disaster after disaster until he is forced to join an Arab raiding party disguised as Riff-Raff. Eventually, he returns to Fort Zinderneuf with the plans of the secret wash-houses of Charing Cross Station and is decorated with the Legion D'Honeure 3rd Class for emptying Arab dustbins in the heat of battle.