The story takes place in the fictional southern town of Yungang City.
The girl Su Wan is introverted and sensitive, and is good at observing the tiny lights and shadows in life. The young man Chen Xu is sunny and gentle, and is the focus of the crowd.
From a collision in the corridor in the first year of junior high school, to their respective worlds after graduating from the third year of junior high school, to an unexpected reunion in the first year of high school and becoming classmates.
Su Wan spent seven years recording a one-way secret love that only she knew about.
There are no bloody fights, no deliberate misunderstandings, only the caution and misses unique to adolescence, and the bland "Long time no see" at the class reunion as an adult.
This is a story about "unavailable love" and "self-growth". It is also an unfinished love letter sent to the past.
