The killer leaves no clue in the show room. After investigation, it is found that CHI is the daughter of WANG who runs big rubber business in Malaysia. As WANG did not accept CHI's boyfriend, CHI eloped with her boyfriend to Hong Kong. Some information of CHING and her photograph are found in NAM's house. It is because NAM has hired a private detective to check her. An employee of the education centre reports that before NAM was killed, he had had secret discussion with another tutor YUEN. Later YUEN is found killed by poison. Incidentally YUNG gets a video tape from a peeping Tom. From it the secret relationship between CHI, YUEN and NAM is exposed. They suspect that the killer is one of those in the education centre.
