Lee Gang-Doo dreamed of becoming a soccer player, but an accident ended those dreams. His father died in the accident and he broke his leg. Lee Gang-Doo spent 3 years in rehab. Now, he doesn't have anything and just wastes his days. Lee Gang-Doo then meets Ha Moon-Soo. Ha Moon-Soo makes architecture models. Ha Moon-Soo also endured an accident that killed her younger sibling. She has suffered from guilt that she survived. She has lived her life earnestly, while suppressing her feelings. After meeting Lee Gang-Doo, Ha Moon-Soo begins to express her hidden feelings.

At a difficult place in his marriage and career, a middle-aged man gets a shot at a do-over when he's transformed back into his 18-year-old body.

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.

Kim Gwan-Chul used to work as an accountant, but now he works as a chief for a company. He is man who follows his principles and uses common sense. He also stands up for those in weaker positions.

Comedy following Cho Seok's ridiculous but hilarious adventures with his girlfriend-turned-wife Ae Bong, their dogs, older brother Jo Joon, and parents. Based on the popular webtoon series of the same name.