Cost engineer Cheng Yan purchases an apartment in Yunqi Residence outright to bring his mother there to enjoy her retirement. However, the neighboring Ma family demands an additional 300,000 yuan, claiming they are owed the difference in property prices. They repeatedly harass him, frame him, and deliberately cause trouble. Cheng Yan documents everything, while other neighbors step forward to testify, exposing the Ma family's fraudulent petition and malicious rumors. After the Ma family's son's fiancée discovers the truth, she calls off the engagement. With their schemes exposed, the Ma family is forced to pay only a small amount in compensation. The property is eventually sold at a low price, allowing Cheng Yan and his mother to live in peace.