Ying Yiyi thought this was a chance encounter. The world is such a small place. After a breakup, you could meet your ex just by walking out.
Han Yinmo thought this was just a normal love, but it wasn't until he had no more information about the other person after the breakup that he realized that the world was so big that he hadn't seen each other for several years after the breakup, so he started a deliberate reunion.
