Xiao Heng and Liu Yan were neighbors when they were young, and their elementary school and junior high school were in the same school. But the two went to different schools in high school and met at a class reunion in their senior year of high school. They liked each other. They liked each other in the college entrance examination, and they performed exceptionally well in the college entrance examination and got into the same university. Xiao Heng was suffering from a terminal illness, which was still in an advanced stage and could not be cured, so he wrote a letter to Liu Yan before leaving.
Concept: Youth of youth