Marine researcher Shen Muzhou brought back a highly toxic blue-ringed octopus, preparing to hand it over to the aquarium, when it was stolen by a neighbor, Zhao Guilan, at the residential complex's bike shed. Ignoring her daughter's dissuasion, Zhao Guilan stir-fried the octopus and fed it to her younger brother, causing him to die of poisoning. Refusing to reflect on their faults, the Zhao family set up a mourning hall and live-streamed rumors claiming that Shen Muzhou had poisoned him to demand compensation. Shen Muzhou produced surveillance and other evidence, and Qian Xiaotang came forward to testify. Further digging revealed that Zhao Guilan's son, Zhao Zhiyuan, was also involved in extortion, stealing secrets, and kidnapping. The involved individuals were sentenced according to the law. Qian Xiaotang buried her uncle at sea, and with Shen Muzhou's help, started working at the aquarium to popularize safety knowledge.