Su Hang, a top student at University A, met a pen pal whose initials was Hy during a seven-day pen pal activity. Over the past few years, they have kept in touch. After graduation, Su Hang became a well-known columnist, and met Lu Haoyuan, the CEO who had just taken over HK's domestic headquarters, during an interview. Since then, there have been various wonderful intersections between the two people who were originally unrelated. Is this a coincidence, or is it? The reunion with Han Yi, a senior at the same school's medical school, also caused subtle changes in Suhang's life. And Su Hang also began to doubt the identity of her pen pal Hy. Who was the person who had lived in her heart for seven years?