Hilary Manningham-Butler

The year is 1929. As the world teeters on the brink of a global recession, Bletchley Park plays host to a rather special event. MI5 is celebrating its 20th anniversary, and a select band of former and current employees are gathering for a weekend of music, dance, and heavy drinking. Among them is Sir Hilary Manningham Butler, a middle-aged woman whose entire adult life has been spent masquerading as a man. She doesn't know why she has been invited, but it is clear she is not the only one with things to hide.

Seville, 1931. Six months after the loss of the British airship the R101, a German Zeppelin is coming in to land in Southern Spain. Hilary Manningham-Butler is an MI5 operative eking out a pitiful existence on the Rock of Gibraltar. The offer of a job in the Americas provides a potential life line, but there are strings attached. First she must prove her mettle to her masters in London, and that means stepping on board the Richthofen before the airship leaves Seville.