Christmas Spirits (Spirited Storms #1) by Jane Charles

Mary Soares was supposed to spend Christmas, nice and warm on her family's estate in Falkirk, Scotland, tending to their whisky business. However, the English have made smuggling almost impossible, and so order after order is waiting at the distillery until it's safe enough to continue shipments. Most customers understand this. Most customers are reasonable. The Duke of Danby is not most customers. So after a number of demands from His Grace, insisting upon his order, Mary decides to deliver the whisky herself since no one else is available. Benjamin Storm, Earl of Kenley, breathes a sigh of relief when his summons from the Duke of Danby has nothing to do with matrimony or a stack of special licenses. Instead, his uncle just needs Benjamin to travel to Scotland and procure his missing whisky shipment in time for his holiday festivities. The chore sounds easy enough, at least until he encounters a most unusual smuggler on her way to Danby Castle. Benjamin's life may never be the same.