In the autumn of 1985, in Bailu Town, Lin Xiaoman, a sugar factory lab technician, mistook her blind date and took the technician Lu Yi for her matchmaking partner, sparking a comedy of errors. Yet she gradually discovered that this silent and gentle man was actually her pen pal of three years of correspondence. After marriage, she moved with him into a provincial capital tube-shaped apartment building, where her poor memory was written down by her husband in a notebook; living apart in two places, they sustained their longing through letter after letter. Years later, returning beneath the osmanthus tree, the backs of the accumulated sugar wrappers pieced together a confession: Lin Xiaoman, marry Lu Yi, for a lifetime. An era of pure love, sweet to the core.