When ninety-one-year-old Alice Hoffman dies alone in her top-floor flat on a busy London road, it's taken as an example of what has gone wrong with modern society: She slipped through the cracks in a failing system. But detectives Arthur Bryant and John May of the Peculiar Crimes Unit have their doubts. Mrs. Hoffman was apparently once a government security expert, though no one can quite remember her. When a link emerges between the old lady and a diplomat trying to flee the country, it seems that an impossible murder has been committed. Mrs. Hoffman wasn't the only one at risk. Bryant is convinced that other forgotten women with hidden talents are also in danger. And, curiously, they all own models of London Bridge.