Duan finds out that her sister is having an affair with her husband so she turns her into a zombie using some drug. At 49:19, she lusts on her sister's boyfriend (bespectacled guy) while secretly watching him take a bath. She enters his bedroom later and has sex with him. She also screws him the second time around with her nurse outfit on, and the third time when he's already a zombie. Duan's husband is already bitten by her sister when she first screws her sister's boyfriend. The description says he will turn into a zombie later, but it is only in Duan's dream that he rises and becomes one.
