Hot Zone by Cindy Dees

Army Captain, Tessa Marconi, Faces Greatest Battle in History in, Hot Zone, a Romantic Suspense from Cindy Dees

Failure has never been an option for Captain Tessa Marconi, even when the mission requires experimental time-travel to ancient Greece to secure a technology component hidden by aliens.

Landing in the middle of the Persian army on the eve of its greatest battle wasn’t part of the plan.
Neither was the charismatic and smoking-hot sorcerer whose sex appeal stands to derail her entire mission.
But when they end up fugitives, on the run together, they must find a way to corral the wild sparks between them if they’re to survive and find a way back to their respective homes. It’s a literal race against time.