10 years after “Marrying the Mafia 1”. The three J’s established an architecture company and have become well-known business. They hold pens instead of fists in their hands but things still happen around them and now even bother their children.

Due to an unplanned pregnancy, Ha No Ra married young and dropped out of school. But after two decades as a housewife, she finally gets the chance to experience college, alongside her 20-year-old son Kim Min Soo and his girlfriend Oh Hye Mi. Further complicating things, No Ra already has a strained student-teacher relationship, as her husband Kim Woo Chul and her first love Cha Hyun Suk wind up being her professors.

Eun Ha-Won is a college student. She is a bright girl who wants to be a veterinarian, but at home she is lonely. She is isolated from her family members. Eun Ha-Won lives with father, step-mother and step-sister after her mother died in a car accident. One day, she helps a mysterious old man. The old man suggests to her to live in a mansion and pursue her dream of becoming a veterinarian. Since than, she moves into the mansion and lives with three cousins Kang Ji-Woon, Kang Hyun-Min, Kang Seo-Woo and their bodyguard Lee Yoon-Sung.