A popular kindergarten becomes famous for its yellow steamed cakes, but secretly adds industrial lead chromate yellow pigment in violation of regulations. Kindergarten teacher Shen Youning discovers that several children have been poisoned. The evidence she has preserved is destroyed by the school, and edited surveillance footage is used to frame her for child abuse, triggering online harassment and costing her her job. Refusing to give in to threats, she joins forces with the victims' parents and an insider from the school kitchen to gather test reports, receipts, audio and video recordings, and other evidence. Together, they fight the principal's manipulation of public opinion, bribery, and intimidation, expose the truth about the poisoning of the children, help bring the case to justice, secure justice for the affected families, and push for improvements in school food safety oversight.