Borrowed from the Secret Intelligence Service cipher department to assist Briers Allerdale - a field agent returning to 1920s London with news of a dangerous anarchist plot - Miles Siward moves into a 'couples only' boarding house, posing as Allerdale’s 'wife'. Miles relishes the opportunity to allow his alter ego, Millie, to spread her wings but if Miles wants the other agent’s respect he can never betray how much he enjoys being Millie nor how attractive he finds Allerdale. Pursuing a ruthless enemy who wants to throw Europe back into the horrors of the Great War, Briers and Miles are helped and hindered by nosy landladies, water board officials, suave gentlemen representing foreign powers and their own increasing attraction to each other. Will they catch their quarry? Will they find love? Could they hope for both? The clock is ticking.

A pantomime dame taking liberties with the chorus line? Sounds like a job for Millie Carstairs!

Miles Siward and Briers Allerdale return for another thrilling Jazz Age adventure. “Silk stockings on expenses.” Miles’s aristocratic mother has information of importance to the British Government and he must escort her home from Bucharest immediately, but their plans go violently awry and Miles and Lady Siward find themselves on a train to Belgrade - where Miles’s lover is posted. Since their pursuers are looking for a man and a woman, might two women slip past them unnoticed? "Is anyone on this train who they say they are?" Briers doesn’t know whether to kiss Miles or punch him but is delighted to accompany him and his mother on their journey. All he has to do is keep an eye open for their enemies - but who exactly are they; the enormous Russian, the sinister priest, the handsome jazz pianist, or maybe the winsome young movie star? And his mother-in-law might just be the most terrifying of all! All aboard for the ride of a lifetime, with a cast of characters you'll never forget!