The Rum and The Fox by Emma V Leech

Lady Keziah Todd is desperate.

Surely the daughter of a Viscount, even an impoverished one, ought to be able to live, just a little? But her father, Lord Rennard, is a violent man, and one that is hard to thwart as he harshly restricts Keziah’s society.
When Keziah learns of her father’s plans to marry the recently widowed and fabulously wealthy, Lady Ashwicke, it doesn’t take the lovely Lady Todd long to realise that the woman’s only son, Felix – the new Duke of Chartley, is a inconvenience that her father will remove with haste .

Felix might be a pink of the ton, but feisty Keziah believes he has more hair than wit and is no match for her cunning father. Unable to live with the good natured duke’s death on her conscience, Keziah takes a risk, and Felix’s life in her hands.