Deng Meijuan (Lv Zhong), an elderly person living alone, is worried because she often receives harassing phone calls, but her eldest son Da Jun (Feng Yuanzheng) and eldest daughter-in-law (Qin Hailu) think that it is a delusion caused by the old man's widowhood. Old Deng tried to communicate with his youngest son Xiao Bing (Qin Hao), but it turned into a quarrel because he couldn't stand the living habits of his homosexual son. In this way, Old Deng became an intruder in the lives of his two sons and lived in an old house out of tune. As time went by, the burglary in the community and the pranks in Da Jun's home gradually made the family alert. At this time, Old Deng met a wandering teenager (Shi Liu) and kindly let him stay at home. But the incident did not subside, but intensified. The two brothers finally discovered that all the incidents were closely related to what happened to their mother in the construction of the Third Front decades ago...