Contains spoilers for this episode and earlier episodes.
Gang-tae reaches the mansion and thanks Moon-young for saving him when they were children, but refuses her request to stay for her sake. His argument with Sang-tae changes that decision. Sang-tae wants to illustrate Moon-young's books and live in the house; when Gang-tae tears up the contract, his brother insists that he belongs to himself. A flashback explains Gang-tae's guilt about the frozen lake. After saying he wished his brother would die, he hesitated when Sang-tae fell through the ice, then returned to rescue him. Gang-tae was left struggling in the water until Moon-young helped him. In the present, he brings his bags to the mansion.
The new household starts with rules about Sang-tae's working days and weekends, followed by cleaning and a shared breakfast. Moon-young stops Sang-tae from entering the basement by telling him Bluebeard's story, keeping the locked room tied to her own memories. At the hospital, Eun-ja mistakes Moon-young for her daughter, upsetting her and disrupting the literature class. Moon-young angrily rejects the woman's insistence that she is her mother. Sang-in urges Gang-tae to move out, claiming he alone understands how to handle the author. That night, Moon-young relives her mother's threats in a nightmare and cannot move. Gang-tae hears her crying, enters the bedroom and stays beside her despite her pleas for him to leave.