To Sir Gideon Landor, an English naval prisoner, Delphine Dalgleish is a Parisian trifle, as pretty-and as useless-as a porcelain doll, who would think nothing of turning him over to the French legion. To Delphine Dalgleish, he's an ice-cool double agent whom she despises for his treachery.

But these two are about to find out how wrong first impressions can be. In the midst of the Peninsular War, Sir Gideon has orders to crack the Grand Paris Cypher, a code created for Napoleon. Meanwhile the emperor himself sends Delphine on a delicate espionage mission to London. Gideon and Delphine may manage to defend their dangerous secrets, but not their hearts. As passion takes hold, it is time to decipher their own complex code of love.