A set of movie posters - The Secret of the Box - is shared with everyone. Independent jewelry designer Li Xinran lives alone in Shenzhen with her 6-year-old son Xiaoxiang. Although she is busy at work and occasionally neglects to accompany Xiaoxiang, she is still with her best friend Cheng.With the help of Cheng Cheng and her boyfriend Gu Zheng, the life of mother and son is surrounded by happiness.However, the arrival of an email broke this little beauty.