In a used car lot, a corpse is found. It has been burnt seriously. The only hints about the identity are the feminine gender and the letters “TL” on her necklace. FUNG asks the public to supply useful information through the mass media. The next morning a teacher working in an evening institute. The identity of the corpse is clarified. She is LAI and has disappeared for three days. On the other hand, the press receives information from CHING who tells the press that LAI killed her daughter in a traffic accident one year ago. YUNG goes to ask CHING but cannot find her. He suspects that LAI was killed by CHING who wanted to avenge her daughter's death. More background of LAI is disclosed. Before working as a teacher in the evening institute, LAI worked as CHEUNG's secretary. She was dismissed by CHEUNG's wife who was discontented with the intimate relationship between CHEUNG and LAI.… ...

FUNG does not agree with YUNG. She refuses to continue the investigation as it is a waste of time and resources of the police. CHIT uses YUNG's idea as the main theme of her novel. She realizes that if YUNG is correct, LAI's situation is dangerous as she may be killed by CHEUNG who wants to keep his secret. Meanwhile the police find LAI and CHEUNG in a flat. CHEUNG is dead. LAI is sent to the hospital. When she regains her consciousness, she reports that CHEUNG attacked her so as to keep his secret. It happened as YUNG suggested. However it is found that CHEUNG was not killed by a knife. Instead he was poisoned. CHEUNG's wife declares that she killed CHEUNG with pesticide as she knew that CHEUNG was not loyal to her. The case is solved.