Brother's Girl: Ki-joon, who lived alone with his younger brother Sang-woo, is worried about Hye-ran, who was the mistress of his father who died in an accident not long ago. Hye-ran had no place to go since their father’s support had been cut off. She had no plans to move away and Sang-woo is into her. Meanwhile, Hye-ran is not satisfied with her sexual relationships with Sang-woo and she is worried about Ki-joon’s mind.