The Strangeways think their days of globe-trotting detective work are behind them, but little do they know that a disturbing mystery is lurking in their own front yard. Detective Nigel Strangeways and his wife, Georgia, have moved to the countryside and settled into sedentary bliss. It seems their days of traipsing the globe and parsing criminal entanglements are behind them. But when a letter arrives commanding the couple to tend their hedges, the most menial of domestic duties uncovers a secret that propels the couple out of their cozy life and into the peril of a power-hungry plot. With the help of Nigel's uncle, Sir John Strangeways, the couple learns of a treasonous conspiracy bigger than their small town. To expose the sinister schemers, Georgia must risk her life and infiltrate a group of fascist sympathisers before they succeed in their plan to overthrow the government.