In the autumn of 1999, seven-year-old Cheng Xiaoyu squatted at the entrance of Qingshi Alley and sobbed while holding a tin biscuit box. Lin Yuan, the new man who moved next door, broke the last chestnut cake in half. From then on, the two children from a single-parent family became half shadows of each other. They shared crooked notes in textbooks, shared a pair of headphones to listen to Jay Chou in an old stationery store, and sealed their secrets in an iron box under the old ginkgo tree.
On a rainy night in 2008, 16-year-old Lin Yuan clutched the test sheet outside the operating room door and looked through the glass at his father, who was covered in tubes. Cheng Xiaoyu braved the rain to bring him the New Year's money he had saved for seven years, but heard an argument outside the ward: "If I hadn't taken care of you, I would have remarried a long time ago." The bottle rack she knocked over when she turned around woke up the voice-activated light in the corridor, and also woke up the young man's cautious love.
Ten years later, Cheng Xiaoyu took his yellowed classmates back to his hometown to teach, and found that there was still a faded poster of the lyrics of "Qili Xiang" on the wall of his old house. On the first day when Lin Yuan took over as the director of the emergency department of the county hospital, he found a bookmark made of ginkgo leaves in the pocket of the unconscious old man. On the back was written in faded ballpoint pen: "Brother Yuan said that I look good in a white skirt today." When the demolition team was about to knock down the old ginkgo tree, the two people trapped in their memories finally opened the moldy love letter in the iron box and discovered the seventeen summers they had missed each other.
