Codename Winter — Aubrey Ross

After the Gathosians invade Earth and enslave its surviving population, Winter is forced to work in an alien-run refinery. When Ulrick Brant rescues her from an even worse fate, she has a new choice -- become an “ambassador”, a sex slave to the invaders. Quickly recruited as a spy for the Resistance, Winter has her first task -- seduce Ulrick, the Gathosians' enforcer on Earth, to learn the location of Earth's potential savior.

Ulrick hates the Gathosians, who force him to enslave world after world against his will. He doesn't mind helping the Resistance, but he won't be used. Before Winter realizes he's discovered her deception, he has her naked and in restraints. Even through his anger, he can't fight the electric attraction between them. But if he agrees to aid the Resistance, it will be on his terms.

Winter is dazzled by the pleasure they share but the Resistance won't wait forever. Danger is closing in, and Ulrick must choose his final role -- ruthless invader or freedom fighter.