Outlander

Not sure if this is the right fit?

Consider An Extraordinary Union by Alyssa Cole.

“This is a character-forward historical romance that layers clandestine missions over wartime urgency, anchored by a formerly enslaved protagonist with an eidetic memory. The pleasure comes from high-stakes setups, oppositions of loyalty, and scenes that trade between danger and growing intimacy. Limitations: genre conventions reappear (meet-cute → escalating tension → confession) and some readers will find long planning or logistical sequences interrupt the romantic propulsion. Best taken as an emotionally driven, plot-tinged love story rather than a strict history primer.”