He loves his younger sister but ends up having an affair with his older sister. This young man deeply loves a beautiful girl he intends to marry, so he often visits his girlfriend's house. On his first visit, he was impressed by the beauty of his girlfriend's older sister; he didn't expect her to be so beautiful. After a few visits, the older sister developed feelings for him. One time when his girlfriend was away, the older sister initiated an affair with this young man.