Zhen Chen (Jang Dong-yoon) visits Korea when his Korean-Chinese father asks to see his wife once again before he dies. When he finds his mother, she is not what he expected. Working in a bar and living with some hoodlum, Chen cannot understand his mother’s choice in men and occupation, and returns to China hurt and disappointed. But when he starts reading a notebook she gave him, learns about her past and the tiny age difference between them, the mystery between mother (Lee Na-young) and son emerges: What made her leave husband and son for Korea? Chen learns that his mother is a North Korean refugee who was sold as a bride to a Chinese-Korean man (Oh Kwang-rok), beginning a life of tragedy. And herein lies the paradox of the title. Were there ever any beautiful days?