When ancient book restorer Shen Zhiyi took over the reorganization project of the city library, he unexpectedly found half an unsent love letter hidden in an old book from the Republic of China. The inscription "Xing Zhi" was smudged in ink, as if it contained unspoken regrets. Lu Xingzhi, the library consultant who was responsible for connecting her, had his fingertips tremble slightly when he saw the book - it was an object left behind by his grandfather. The annotations in the book contained the secret of his missing life with a woman.
