After the fall of her kingdom, Princess Lotte is sentenced to death to appease a powerful witch army. To save her, Prince Eric strikes a deal with his father to make Lotte his personal slave maid, subjecting her to a month of grueling and humiliating conditioning. Driven by their childhood bond, Lotte endures the degradation and submits to Eric's will in a desperate bid for survival.
After being shown a vision of the brutal fate awaiting Princess Lotte if she fails to submit, Prince Eric decides to intensify her slave maid training to "save" her. Lotte is forced to endure the use of enlarging tools and a pulsating monster, even while performing her household chores. As she struggles between her pride and her survival, Lotte gradually accepts her role, demonstrating her progress through degrading exercises to earn Eric's approval.
Prince Eric utilizes a controllable monster to push Princess Lotte's training to a depraved extreme, forcing her into total physical and mental submission. Despite King Karl's skepticism regarding Lotte's loyalty, Eric successfully breaks her spirit with the help of the provocative Keela, transforming the Princess into a devoted slave. Meanwhile, Eric begins investigating the identity of the assassins responsible for the attack on his life and the death of Breidonner.
Lotte completes her transformation into a slave maid by receiving cursed piercings and defeating a Cyclops to prove her ability to protect Eric. Amidst political betrayals and a brutal war in the south, the two strengthen their bond and conceive a child. Returning as heroes, Lotte's absolute devotion to Eric is cemented as they embrace their future together.