The Captivation by Natasha Rostova
Classic Black Lace historical action, set during revolutionary Russia...
In 1917, war-torn Russia is teetering on the brink of revolution. A Russian princess, Katya Leskova, and her family are forced to leave their estate when a mob threatens their lives. Katya ends up in the encampment of a rebel Cossack army; the men have not seen a woman for months and their libidos are out of control.
When the Cossack captain discovers Katya's privileged background he has no intention of letting her leave the camp. Against the turbulent background of a country in turmoil, Katya and the captain become involved in an erotic struggle to prove their power over each other.