Her Duke in Shining Armor by Emma Linfield

So dark, so deep, the secrets that you keep…
Eleanor Stanley, daughter of the Duke of Brisdane, is certainly not the apple of her father’s eye.
Rebellious and blatantly outspoken about her dislike for the hypocrisy of the ton, she’s earned herself not only a bluestocking reputation but also the nickname ‘Lady Disdain.”
Aaron Bravolt, Duke of Oberton, never expected to catch one Lady Eleanor sneaking a servant child out at night in order to spare her from her father’s wrath. But his determination to decrypt the puzzling lady has consequences he couldn’t have foreseen.
With his own assets under attack by a mysterious adversary, Aaron has only eighteen hours to discover what really happened to the Duke of Brisdane’s late wife and to keep Eleanor from being taken away from him forever.