Twenty-eight-year-old Yi Ning is a senior grinding technician at a steel structure factory. He can use an angle grinder to polish welds as smooth as a mirror. Five years later, her former lover Zhou Ye parachuted in to become a project quality inspector. The man who left without saying goodbye now scrutinizes every step of her process with strict standards.
During the internship, they were forced to work together again. Excessive polishing will result in insufficient load-bearing of the thin steel plate, and residual welding will accelerate corrosion in the rainy season. Yi Ning searches for a balance between millimeters, just like finding a fulcrum between love and reality. The temperature difference causes cracks on the polished surface, which can be modified with a grinding wheel, but the estrangement in the heart cannot be completely eliminated.
The two spent countless days and nights side by side, overcoming the pressure of the construction schedule and process difficulties. Just when Yi Ning thought she could regain her old relationship, she discovered that Zhou Ye had already planned a future without her. She finally understood that some feelings are like over-polished steel, the surface is perfect, but the internal structure has long since failed.
