In October, the old alleys of Jiangcheng are shrouded in wet, cold and thick fog all year round, and even time seems to slow down here. 27-Year-old Lin Shen resigned from a high-pressure job in a first-tier city and opened a used book shop here. Guarding a room full of old books and letters, he lived a peaceful life without fighting against the world, until a gray-haired old man opened the door of the shop and completely broke the peace. The old man is Mrs. Chen, who is nearly seventy years old. She has been searching for an old letter to her son for thirty years. The son she said left home in anger when he was young. She rushed to the post office with a letter of apology, but accidentally lost it in a foggy alley. From then on, this letter became her obsession for half her life, and it also became a concern that she dared not touch. Lin Shen couldn't bear it, so he rummaged through the old things in the shop, and found the yellowed off-white envelope in the old wooden box left by the shop owner. But after opening the letter, she realized that it was no ordinary mother-son reconciliation letter at all. The lines were filled with overwhelming guilt and secrets, and it was not at all like the simple dispute that Granny Chen said. Then, in the middle of the night, a mysterious man quietly came to the door and asked for the letter to Ayu. The few words from the neighbors revealed the shocking past that had been hidden for thirty years. Layers of suspense spread in the mist. This old letter spanning half a lifetime hides secrets that everyone has deliberately buried, and it also leads to a redemption that has been long overdue. The story is free of blood and adventure, and is based on street fireworks. It interweaves suspense and warmth, and tells the story of half-life obsession and self-forgiveness. The ending is heartbreaking in a twist, showing the softness of human nature.
