It tells the story of Guan Xiaozheng and his mother searching for people who litter cigarette butts in the community. After discovering the cigarette butts, they first excluded their non-smoking neighbors and then suspected that it was caused by a tall and thin elderly person who had just moved in. Although the old man denied it, Guan Xiaozheng and his mother discovered more evidence through observation and ultimately confirmed that it was the old man who did it. They tried to solve the problem through posting notices and direct communication, but the effect was limited. Later, the elderly man's son came forward and promised to solve the problem, and the cigarette butt issue improved to some extent. At the same time, the chapter also covers garbage classification and safety issues. Guan Xiaozheng and his mother expressed concern about Mrs. Liu's behavior of picking up cardboard boxes, fearing that it might cause a fire. Finally, the story ends with a smell of smoke, indicating the possibility of a fire.