Eun-Seol, a woman forged in the fires of battle as a juvenile soldier, steps into a world far removed from the battlefield when she is taken in as the daughter-in-law of Ki Hae-Woon, the powerful Imperial General of the Baek Empire. This shocking development takes everyone by surprise—especially since Hae-Woon's eldest son, Baekwoon, is already known to be married!

But the surprises don't end there. In a stunning declaration of power and ambition, General Hae-Woon announces that the successor to his family lineage will be Eun-Seol’s future unborn child, a child that doesn't even exist yet. This immediately throws Eun-Seol into a dangerous whirlpool of imperial politics and domestic conflict.

The drama heightens when the General himself, Ki Hae-Woon, comes to her chambers on a beautiful, bright moonlit night. What exactly does this powerful man, who is supposed to be her father-in-law, intend to do? Trapped between duty, survival, and overwhelming desire, Eun-Seol must navigate this dangerous game where morality is thrown out the window. Dive into this intense historical romance and uncover the secrets of a truly 'immoral night'!