May 1940:- At the Halcyon hotel in London discreet manager Richard Garland turns a blind eye when the promiscuous owner Lord Hamilton smuggles in his flighty mistress Charity Lambert to sit in on a secret meeting of the appeasement party. When his wife Lady Hamilton arrives unexpectedly Richard and his receptionist daughter Emma, assisted by housekeeper Lilian and porter Feldman, act quickly to prevent her from catching the couple together. Emma is mutually attracted to RAF pilot Freddie, the Hamiltons' elder son who turns up with researcher brother Toby but Betsey, the out-spoken dance band singer, warns Emma that Freddie is out of her league. At a party for Freddie his father's indiscretions are common knowledge with the staff and Lady Hamilton despite the pair putting up a united front. They are all observed by American journalist Joe O'Hara, whose plan to expose Hamilton's political stance in a broadcast home leads to disaster.