A gentleman cast out by society.
A lady who refuses to abandon him.
A scandal that may bind their hearts?or destroy them both.

Harry Coatsworth has never envied a title or pursued an heiress. Blessed with charm, fortune, and a promising diplomatic career, he prefers freedom to matrimony?until a powerful family asks him to befriend an unconventional debutante during her first London Season.

Marianne Trevarthan would rather discuss books and politics than perfect the accomplishments expected of a marquess's sister. Although her family is determined to secure an advantageous match, Marianne has little patience for fashionable gentlemen?yet beneath Harry's easy wit she discovers an intelligent and honorable man.

Just as Harry resolves to prove his intentions, duty calls him into a secret government mission. To infiltrate a conspiracy threatening the Crown, he must deceive his friends, cultivate dangerous companions, and allow London society to believe the worst of him.

One by one, the doors of the aristocracy close.
Only Marianne remains loyal.

When she risks her reputation to warn Harry of approaching danger, one reckless act leaves them both at the center of a scandal. Now Harry must choose between the mission that demands his silence and the woman whose faith in him could cost her everything.

Portman Square is a clean Regency-set romance featuring friends to lovers, political intrigue, a bluestocking heroine, a charming diplomat, and a love tested by secrets, scandal, and sacrifice.