Tommy and Tuppence, a couple in love, are so broke that they are willing to do whatever it takes to earn some money. England after the Great War does not offer so many options, so they decide to establish their own business with the logo "willing to do anything, go anywhere". The first assignment comes shortly after and it seems deceptively easy. Tuppence has to pose as an American lady, called Jane Finn. What the couple did not know however, was the fact the Jane was an important figure for England's economy and recovery. Will the danger they will find themselves in be worth it or will they lose more than they could have expected? "The Secret Adversary" holds the answers.