Shen Wanqiu, a temporary worker at a state-owned textile factory, after experiencing a shift replacement being verbally denied by regular worker Zhou Xueping, resolves to no longer suffer in silence. She creates a set of "human relations ledgers," demanding that all favors and interactions be put in writing with receipts, fingerprints, and cross-page seals, and sets a "thirty-day billing period." Taking her adopted daughter Shen Doudou, she works hard in the workshop while using these rules to deal with Zhou Xueping, who tries to take advantage of her, and Zhou's weak younger brother Zhou Qiming (Shen Wanqiu's future husband). Her core motivation is to protect Doudou, uncover Doudou's background, and fight for the rights and respect she deserves.