The narrator tells us that li yong, the murderer, is a retarded man who was raised by his family to protect him from being insulted. His father, Mr. Li, tried to frame him for the murders of his son, but his true identity is not known. The narrator explains that his father hid his son in order to cover up his crimes, but that his true nature knows nothing of the murders. He is just a poor man. Worried that his son will never see him again, the narrator goes outside to get air. He hears the sound of butterflies and sees that it is xiaoli's mother, who had saved him from poisoning