The story begins with the rebirth of the female lead, Elara. In her past life, she was a wealthy young lady from modern society, betrayed by her fiancé and cousin, and pushed into an icy river to die. Filled with immense hatred and unwillingness, she awakens in a world resembling medieval Europe, reborn as a lowly serf girl suffering from hardship and abuse.
Facing a desperate situation and a cruel reality, Elara relies on her past memories and indomitable will, determined to struggle for survival in this new world. However, fate leads her to unexpectedly catch the attention of Duke Reinhardt, the most powerful nobleman in the region, known for his dark, obsessive personality and feared reputation as the "Mad Duke." Attracted by something unique about Elara, the Duke takes her away by force, treating her as his exclusive possession, confining her like a "sparrow in his palm."
Within the Duke's castle, Elara endures the pain of being controlled and "disciplined" while simultaneously using her intelligence and knowledge from her past life to seek opportunities for survival and secretly build her strength. She must navigate the Duke's volatile "mad dog" behavior and suffocating possessiveness, while also maneuvering through complex noble politics, church influence, and estate affairs, gradually showing astonishing resilience and growth.
As time passes, through their forced entanglement, Elara begins to glimpse the trauma and vulnerability hidden beneath the Duke's violent exterior. Meanwhile, the Duke finds himself increasingly drawn to and affected by this untamable "sparrow," and cracks begin to appear in his icy heart. After experiencing external political turmoil, court intrigues, and even the crucible of war, the two are forced to cooperate, their relationship becoming exceedingly complex—a mixture of coercion, hatred, dependence, and a thread of unconscious mutual salvation.
Ultimately, Elara transforms from a serf merely struggling to survive into a woman of wisdom and strength capable of navigating the darkness. The obsessive and mad Duke, through their mutual torment and redemption, begins to confront his inner self and seek change. The story revolves around themes of coercive love, the fight for survival, personal growth, and eventual mutual redemption, depicting a tale of intense, painful, yet compelling love and hate set against a medieval backdrop.