Check out Amy Corvin's "I Bid One American"

She’s an American heiress nobody wants; he’s a Duke every woman is after.

When Nathaniel, Duke of Peckham, meets Charlotte, he’s suspicious of her indifference. Too many women have sought—and failed—to catch him. However, Charlotte is more interested in dead pharaohs than English dukes.
Her pretended immunity vanishes, however, when a debutante seeking to entrap Nathaniel gets murdered. All too soon, his reputation as a misogynist makes him a suspect, and Charlotte impulsively comes to his aide.
Unfortunately, both are unaware that a highwayman interested in rich heiresses is following Charlotte. And that another debutante lies dead in Nathaniel’s carriage.

Some nights just don’t go as planned.


EXCERPT:

Now, he glanced in the direction of the doorway and seemed to stiffen. Charlotte followed the direction of his gaze with dismay.
“Say something,” he said, bending over to whisper urgently in Charlotte’s ear. “Anything—just don’t leave me alone with her. Please, you’ve got to help me!”
Charlotte jumped, startled as his warm breath played over her neck.
Lady Beatrice floated toward them across the flagstone terrace, her steps quickening as she noticed them. “Your Grace,” she called.
“I don’t see why you think I should—” Charlotte paused as Lady Beatrice neared.
What did he want from Charlotte? Did he hope to make Lady Beatrice jealous? Charlotte could almost smell the faint, metallic odor of an iron trap following Lady Beatrice like stale perfume. Suddenly, Charlotte didn’t trust either of her companions in the soft, cold darkness of the terrace.
Lady Beatrice placed a light hand on the man’s sleeve. He gazed beseechingly into Charlotte’s eyes and she wavered in confusion. She could not protect him from Lady Beatrice, even if that was what he wanted.
Unable to resist the entreaty in his eyes, Charlotte said the first thing that came to mind. “I don’t see why you want me to explain the differences between the Garden Tiger and the, um, Buttoned Snout again. It’s not difficult, you know. A child could do it. All you have to do is concentrate.”
He had asked for her help. A lecture on moths was the best she could do considering the circumstances.
“Yes,” he said, his tone humble. “But I’m new to this, uh, that is, I’ve never appreciated moths before. Couldn’t you just go over it one more time?”
“What are you doing out here, Your Grace?” Lady Beatrice asked, her tone sharp. She glanced from him to Charlotte. “Miss Haywood,” she reluctantly acknowledged. Then she gazed at him, tilting her head back to make him feel taller and emphasize the lovely line of her throat and impressively bare bosom. She smiled and gave a light, tinkling laugh when his eyes followed that perfect curve of flesh. “You don’t wish to be compromised, do you? With poor Miss Haywood?”
Her artless question made it clear she knew exactly who he would prefer to compromise. And it wasn’t poor Miss Haywood.
“We’re identifying moths, Lady Beatrice. I doubt seriously whether anyone will find themselves compromised. Don’t you agree, Your Excellency?” Charlotte said, unable to resist teasing Lady Beatrice by deliberately using the wrong title for the duke. She knew it would annoy her. Charlotte just hoped she had understood the gleam in His Grace’s eyes correctly and that it would not annoy him.
At least not unduly.