The film tells the romantic story of the protagonist Qianniu (Cha Tae-hyun) and his new "wild" girlfriend Xingxing (Vice Song), from falling in love to getting married. Xingxing was Qianniu's first love in elementary school. Because she was not fluent in Korean, she was often bullied by her classmates. Qianniu could not forget his ex "her" at first. Until one day, Qianniu met his first love Xingxing again, and he walked into the marriage hall with her despite the opposition of the people around him. Unexpectedly, he faced troubles beyond his imagination.