The Duke's Secret Mistress

Quick answer: 6 episodes, English original audio, and episodes 1–6 play right here tonight.

The young lord of Everfrost City was ambushed and fell into a coma from severe injuries. The ambitious Oliver, coveting the territory, constantly pressured the young lord’s wife, Aixi. With nowhere left to turn, Aixi made a secret deal with Freeman, the ruler of Everfrost City, in order to survive and preserve any hope of succession. What began as a mutual bargain gradually bred deep feelings through one crisis after another. Oliver kept devising schemes to frame them, repeatedly pushing them into danger. Just as their relationship was becoming stable, the gravely injured young lord unexpectedly woke.

The secret they had buried was on the verge of being exposed, and guilt and love tormented Aixi endlessly. In the end, the young lord died of illness. Unable to bear the weight of the past, Aixi left Everfrost City pregnant and went into hiding in a remote border town. Freeman did not force her to return; instead, he silently protected her and her child from the shadows for a full year. When a riot suddenly broke out at the border, the two met again. Letting go of the barriers in their hearts and the pain of the past, they chose to face their feelings for each other.