Miss Sinclair's Secret (The Secret Series #4)
Amylynn Bright

Nathaniel Johnson is an American patriot whose only goal is to return to the country he loves with his recently located brother, a sailor impressed by the British. The money offered to escort a young English woman to the United States is too much to pass up when he’s desperately trying to save his family’s shipping empire. The beautiful lady spins a ridiculous tale about looking for her father, but Nate has powerful reasons to believe she’s a spy for the Crown. He’ll help her on her quest, at least until he can prove her villainous intent.
Will Anna’s secret destroy his country and be his undoing?