Most Ardently by L.L. Muir

A treasure hunt in Scotland with impossible consequences…
Violet Cottsweather has three days to find a long-lost treasure before anyone realizes she doesn’t belong. Her sister’s life may depend upon it. Posing as a servant at the Earl of Ashmore’s country gathering is a risk, but it’s the only way to search the estate unnoticed. Unfortunately, one guest refuses to look the other way.

Louis Condiff came to this Scottish country party as a favor to his cousin. His newly inherited title is worthless, but it’s shiny and new, and he’s looking to rub some elbows far more fine than his own. Instead, he keeps getting distracted by a servant woman who moves with too much grace and pops up in places she doesn’t belong. He’ll go mad if he can’t discover what she’s hiding, and he’s got three days to do it.
It might amount to nothing. Then again, it might mean everything… to them both.