Uncountable Heartbeat

23-Year-old forensic doctor Shen Qingge unexpectedly reunited with 24-year-old mathematician Jiang Chen at the scene of a murder on a rainy night. They were high school classmates and once fell in love with each other, but due to adolescent timidity and a key misunderstanding - she panicked and erased the secretly drawn sketch of his profile, but he misinterpreted it as rejection and withdrew the love letter he failed to deliver - making this relationship a deep regret. They met again six years later. By working together to analyze the case, they got in touch with each other unfamiliarly but professionally. Finally, in a cafe, Jiang Chen took out the well-preserved old love letter, and the dusty misunderstanding was resolved. They found that the throb from back then had never gone away. At the end of the story, the two transcended the barriers of time and hugged each other tightly, giving a satisfactory answer to their youth that ended in vain, and opening up their present and future.