He Xi met Song Shu because of a mysterious love letter, but unexpectedly this love letter did not belong to Song Shu. The two don't know where the love letter is going, but they maintain an awkward relationship because of it.
It wasn't until after a mathematics competition that the two made progress while learning from each other, and also developed a sentimental feeling for each other. After passing the high school entrance examination, the two met to enter the same high school. Song Shu, who gradually came to understand his feelings, originally wanted to express his feelings to He Xi after passing the college entrance examination, but instead received news that He Xi was going abroad to study.
Song Shu, who was determined to work side by side with He Xi, was infected with a new virus while going to the countryside for research. He suffered from the disease for seven years, and finally died of illness before He Xi returned to China.
He Xi suddenly remembered that the day before she left the country at the age of nineteen, in the bright sunshine, she fumbled for a leaf-shaped green-backed note from her desk drawer, with a passage written on it -
"The wind will blow regret into your heart
By then you will feel a tightness and heaviness in your chest
Just like a day thirteen years ago
Forget it, let time wash away everything."
The wind took the opportunity to get into the window and caressed her hair. She was too young at the time, and her youth prevented her from noticing that the sunlight following the wind had boldened the two words written very heavily on the paper -
"Regret"
Purpose: Cherish the present moment and enjoy peace and harmony in the world