A cleaning workshop receives industrial alcohol mistakenly sent by a supplier, and owner Gu Zhengchuan isolates it with warning signs, preparing to return it. Neighbor Su Mei ignores the warnings, secretly stealing this hazardous solvent containing methanol home, treating it as liquor, causing her husband Jiang Chengfu to die of poisoning after drinking it. After the incident, Su Mei refuses to admit her fault, conspiring with her son-in-law Sun Zhiyuan to fabricate evidence, attempting to use the deceased as a bargaining chip to extort a huge compensation from the workshop, and even causing a scene at the site and broadcasting for momentum. The police intervene in the investigation, cracking layer by layer mysteries such as account privilege misuse and tag tampering, relying on surveillance, physical evidence, and raw records to restore the truth, clarify responsibilities of all parties, and expose hazardous material management loopholes and human greed.