The Lady and the Spy by Ruth A. Casie

With each encounter her heartbeat quickened. With each encounter his need for her grew stronger.
Lady Patrice Montgomery Edgemont always did what was expected of her and look where that got her, married off by her father into a loveless relationship. She solved the puzzle that was prospective husband number two, another of her father’s choices and quickly made him a distant memory. Lady Patrice is not playing games. She is through with men.

Nikolai Baranov is the son of a Russian grand duke and spy for Tzar Alexander I. When his father and associates are killed, Nikolai doesn’t play games. The only thing worth winning is revenge for his family.

When a blizzard blankets Sommer-by-the-Sea, Lady Patrice is the only one who can help the mysterious wounded Russian she finds in her hunting lodge. It will take Nikolai’s skill as a spy and Lady Patrice’s expertise at solving puzzles to play through and win the game, a happily ever after.