
Young Mother-in-law is a bold story about living together between a young mother-in-law and her son-in-law. Young Mother-in-law ~ Don’t let your father-in-law or wife know! Seon-yeong and Do-han have been married for 3 years. Due to a business failure, Do-han lost his entire family and was forced to move into Seon-yeong’s father’s house, who was living alone. No longer interested in her incompetent husband, Seon-yeong started going to clubs and had an affair with Jeong-hyeon, whom she met there. Seon-yeong was drunk or didn’t come home every day, but Do-han didn’t say anything and only felt more and more resentful.
One day, Seon-yeong received news from her father, who was on a business trip, that her future stepmother would be coming home. Kyung-mi, the young stepmother, arrived first because Seon-yeong’s father’s work schedule was extended. Kyung-mi met Seon-yeong’s father at work and planned to remarry him, but because her father’s work was delayed, she came to the house first. Seon-yeong did not welcome Kyung-mi’s appearance, and when Kyung-mi saw Do-han being ignored by his wife, she comforted him and tried to seduce him to make him hers.
The three people, the young stepmother, daughter, and son-in-law, began a tense and dangerous cohabitation.