When Su Wan was cleaning the balcony, she accidentally picked up a leather diary that had fallen from the balcony opposite. The title page was unsigned and only had a withered blue flower painted on it. Depressed words were recorded in the diary: "He stared at me from the window again" and "That old suitcase cannot be opened." Out of curiosity, Su Wan began to pay attention to her new neighbor - Gu Yan, an old watch restorer with a gentle appearance. She discovered that Gu Yan behaved strangely: he was always playing with old rusty clocks in the studio late at night, and the sound of the collision of parts was particularly clear in the silent corridor; when going out on rainy days, he would always carry a stopped silver pocket watch, and his fingertips would repeatedly rub the dial; and when he saw the blue flower pattern, he would subconsciously tighten the clock screwdriver in his hand, and his knuckles would turn white. As Su Wan continued to get clues from the diary, she was gradually involved in an old case that had been hidden for many years, and at the same time she developed complicated emotions towards Gu Yan. When she thought she was close to the truth, she discovered that the owner of the diary might not be who she thought, and strange clock parts began to appear near her window, making her the target of prying eyes.
