He is a heartbreaker.

Gabriel St. Clair, the Earl of Montgomery, has a reputation for being the most charming gentleman in London. But to Miss Lydia Cecil, he is the man who shattered her heart. Gabriel would rather Lydia hate him than learn the truth: he's a British spy-and his enemies are closing in.

She is a wallflower.

Lydia has settled into a life as a companion for her elderly aunt. But when she witnesses Gabriel gather intelligence on a foreign enemy, she's suddenly thrown into his dangerous game of espionage. To save her life, Gabriel is forced to marry the girl he once abandoned.

Their greatest threat may be their past.

As husband and wife match wits, their greatest threat may not be the assassins on their heels, but learning to set aside their pasts or risk losing their love for good...