Laid-off young maintenance worker Lin Zhou brings the manual transport prototype made in two weeks to the community for trial evaluation. An empty-cart biased wheel, incompatible armrests, narrow corners that cannot be passed, and poor ramp braking after folding make him repeatedly frustrated. Porter Shen Yue does not cover up his flaws, and evaluation lead Gao Ming does not lower standards. Lin Zhou gradually shifts from 'proving himself' to 'solving user problems', completes verifiable corrections in controlled tests, and finally wins a paid trial proposal for one car, regaining the starting point to continue doing things.