The story line mainly revolves around the male protagonist Wang Hao, the female protagonist Su Xiaoye, Liu Qian and Sun Shaoyang. In the memories of the female protagonist, Wang Hao, who had disappeared for five years, suddenly appeared and met Su Xiaoye again, but found that she had an engagement with Sun Shaoyang?Before Wang Hao disappeared, he promised Su Xiaoye to wait for her for two years and get married when he came back.However, when Wang Hao came back and wanted to fulfill his promise, he found that Su Xiaoye was no longer the Su Xiaoye he remembered.But what Wang Hao didn't know was that Su Xiaoye promised to wait for him for two years but had been waiting for four years. With Su Xiaoye, Wang Hao has always been Wang Hao in Su Xiaoye's memory, but she didn't know that she was no longer Su Xiaoye in Wang Hao's memory... During the four years when Su Xiaoye waited for Wang Hao, Sun Shaoyang had been by her side, but she had no choice but to make a marriage contract with Sun Shaoyang under the pressure of reality.Liu Qian and Wang Hao have been secretly in love with him for four years. They are still single when they come back after studying abroad... However, the ending is that later, the four of them have everything, but they are gone.The best of them were forever stayed in that best time.