True Education for Cheating Sister-in-law: An unemployed man. The man has no money and ends up staying with his married older brother's house. His sister-in-law feels sorry for him seeing only playing at home. A man who always watches his sister-in-law's thoughts and actions. Then one day, he found out that his sister-in-law was having an affair and cheating on his brother!! He threatens his sister-in-law about what he found out, so she asks him to keep it a secret and tells him that she will grant all his brother-in-law's requests.