The story of the love and conflicts of each member of a large family, all of whom have unusual names.

Kim Sun Kyung is a retired police officer and father of three sons, Gun Kang, Hyun Chal and Yi Sang.

His eldest son Gun Kang made many wrong decisions in life, ending up being divorced and going bankrupt. Gun Kang gets remarried to Chung Nan. His second son Hyun Chal is the envy of the town and pride of his father. He runs a number of businesses which are quite successful. His wife Woo Mi often sacrificed her happiness for the benefit of the Kim family. As for the last son Yi Sang, he follows in his father's footsteps by becoming a police officer. Oftentimes the father and the son clash each other. As Yi Sang married Eo Young, the daughter of his father's deadly foe, an ex-convict Sun Kyung traced and eventually arrested a long time ago.

"Three brothers" revolves around their relations full of conflicts and love.

The series is described as taking a cheerful look at the lives of its female leads, their families, and friends.

23 years ago, Kang Eun Seol's father, Kang Jae Oh, stole the position of Lee Shin Jun's father. This led to Lee Shin Jun's father to commit suicide with his wife and son. Now 23 years later, Lee Shin Jun, also known as Chase, wants revenge and isn't going to stop until he gets it. He makes Kang Eun Seol fall for him, so that he can get to her father. But there is a twist, Lee Shin Jun has also fallen in love with Kang Eun Seol, but Lee Shin Jun's partner, Park Joo Won loves him too... Later Eun Seol finds out about Shin Jun's revenge plot against her father and she decides to get revenge on him for using her..