His Diamond (His & Hers #3)
Charlotte Russell

Lord James Danforth, one of His Majesty’s more successful spies, returns to England after three years to capture a home-grown assassin. A man of few words but much passion, he has always regretted his decision not to marry Amelia. While tormented by her recent engagement, James is determined to behave as the proper gentleman is he—until he suddenly finds himself thrown into a triangle of romance, suspicion, and betrayal with Amelia and her fiancé.
As these two fiercely loyal individuals—he to his country, she to her friend—race to save the prime minister’s life, can they also reawaken their once burgeoning love and learn to trust one another?