Wei Yingying, a female college student from a poor family, met a little boy named Xin Zhengzheng who had been following her. Because he suffered from PTSD, although he looked 8 years old, he was already 17 years old. A few years later, the grown-up Xin Zhengzheng still couldn't forget his "sister" Wei Yingying. He found Wei Yingying at work and began to pursue the little sister fiercely. But facing the gap between the rich and poor families of both parties, Xin's family engagement and other problems, can they finally get married?