The story is inspired by the cement corpse case in the industrial building in Hui Yiu Kok Street, Tsuen Wan, which shocked Taiwan, Taiwan and Hong Kong in 2016. The victim of the cement corpse case in the industrial building in Hui Yiu Kok Street, Tsuen Wan was a 28-year-old man named Zhang Wanli. He was suspected to be killed by four young people for debt collection. Afterwards, the body was hidden in a homemade cement coffin. The case happened on April 4, 2016. Zhang went missing after allegedly going to the DAN6 unit where the case occurred to collect debts from the tenant. On April 6, Zhang's female friend reported to the police looking for him, and the police listed him as a missing person. The Hong Kong Island Regional Missing Persons Investigation Team found that Zhang had contacted the male tenant of the unit where the case occurred based on the last call record before his disappearance. The target was locked by the address. After checking the surveillance camera screen in the building, it was found that Zhang had taken the elevator upstairs with the male tenant and a man to enter the unit on the day of his disappearance, and he did not appear again afterwards. After that, other people entered and left the unit from time to time, and someone even brought cement. The police tried to contact the male tenant but to no avail. On April 29, the police entered the unit and finally uncovered the case of the body hidden in cement. The deceased was confirmed to be Zhang Wanli. After investigating the case, the police believed that four of the men and women involved fled to Taiwan. After they stayed there for a month, the case caused a sensation in both places. It was also the first case involving law enforcement and extradition regulations in both places after Hong Kong's return. The four young people committed crimes, buried the bodies in horror, and finally fled to Taiwan and hid for nearly half a month. Their mentality of half fleeing and half traveling constituted the prototype of this crime movie.