While PING ON and TIN MAN shop in a department store, they meet the robbery. The robber is caught by PING ON and TIN MAN. The robber threatens that he put a bomb in the department store. Unless he is released, he will not tell the place. TAI YAN arrives he shows nervous. PING ON uses his talent and finds out the bomb. He is appreciated by people. TAI YAN feels unhappy. PING ON is a smart policeman. His wicked wife, YUK HING uses to urge him for early retirement. Under his wife's pressure, he decides to retire. He sets up a detecting house. He continues his aspiration to arrest and clear up criminal cases. PING ON gets minor cases, such as romantic affairs, adultery cases or find the kitten and dog. He feels useless as he cannot display his ability. One day, a lawyer who represents a wealthy man, KIM CHEONG SHAN visits PING ON. He appoints PING ON to investigate a poison case.… ...

PING ON and TIN MAN try to make friend with KWOK YEE. However, she appears to be cool and taciturn, they are unable to keep close to her. In fact, after her husband's decease, KWOK YEE returns home. She takes over the job as housekeeper. The other family members look down on her. She maintains good relationship with WING SHUN and LAI WAH. CHUNG and WAH have the night snack in the kitchen. CHEONG SHAN sees and scolds them being too waste. SHAN puts all the blame on WAH. PING ON follows KWOK YEE, he finds she buy s some rat vermicide. He suspects KWOK YEE but he has no evidence. He asks SHAN to be carefully. KWOK SUNG fonds of LIN SUM's pretty. He uses to molest her.TIN MAN sees and he helps her. KWOK SUNG leaves with anger. TIN MAN has a deep impression on LIN SUM. WING SHUN thinks her sister's death has been caused indirect by CHEONG SHAN. She is over stimulated and has psychosis symptom.… ...

TIN MAN misunderstands LIN SUM hates CHEONG SHAN so she has the intention to kill him. He confronts her. LIN SUM denies and leaves with anger. Actually, LIN SUM is deeply moved by TIN MAN. Due to her revenge has not reached, she feels not suitable to think the love affair. TIN MAN shows difficult to suppress his feeling by rational. He is contradicted. KWOK YEE and LAI WAH go to play bowling. They have conflict with FEI CHEUNG. They all go to police station. CHEONG SHAN feels losing face and scolds them strongly. In fact, LAI WAH married KWOK CHUNG because of her pregnancy. She has been suffered the abortion after her marriage. CHEONG SHAN regards her as a thorn in the flesh. He persuades KWOK CHUNG to make a divorce with LAI WAH and remarry. LAI WAH endures. PING ON investigates step by step. He discloses the family members' complicated relationship. He finds out the clues to clear up the case.… ...

After WING SHUN has been discovered as the murderer, she frankly admits. She has seen her sister's will few years ago that her sister died because she cannot endure CHEONG SHAN's abuse. She hates CHEONG SHAN and waits for the chance to take revenge. WING SHUN becomes crazy and she wants to die together with CHEONG SHAN. Fortunately, PING ON duly stops her. CHEONG SHAN sends WING SHUN to the sanatorium and he never allows her to step in the family. PING ON finds that KWOK YEE also helps WING SHUN in the poison case. As to avoid further family struggle, he hides the truth. He only gives warning to KWOK YEE. KWOK SUNG owes a large amount of debt. He seeks help from KWOK PING. The couple cannot help him. They want to cooperate with KWOK SUNG in collusion. KWOK SUNG pretends to be kidnapped and asks CHEONG SHAN a large amount of ransom. PING ON wants to withdraw but CHEONG SHAN asks him to settle KWOK SUNG's kidnapped case.… ...

CHEONG SHAN scolds KWOK PING and his wife for their disobedience. KWOK PING blames CHEONG SHAN who controls his development outside. He has financial difficulty. He has no other method so he does this. After this issue, the couple is intimidated by CHEONG SHAN and they cannot raise their head. KWOK PING finds he has no position in KIM's family. He wants to get back the ransom for other development. But KWOK SUNG gets the ransom. KWOK PING's hope is gone. KWOK CHUNG knows the past relationship of WAH and ON. He suspects they will become lovers again. His attitude towards WAH turns cool. This makes WAH feel she does not like to stay in KIM's family.

KWOK SUNG owes a large amount of money to the loan shark. He returns home to seek help from father, but he sees CHEONG SHAN died in the blood. He becomes the first witness. PING ON knows the responsible police superintendent, Mr LAW quite well. Superintendent LAW uses PING ON's relationship with KIM 1 s family and invites ON to cooperate with TAI YAN to investigate this case. TAI YAN dissatisfies the high spirit of PING ON. TIN MAN tells LIN SUM about the death of CHEONG SHAN. Apart from showing her shock, LIN SUM seems to hide some secret. PING ON has a series of investigation. He verifies that CHEONG SHAN's neck has been cut which causes his death. The murderer has the intention to arrange as if it is a robbery in order to hide the truth. All the family members have the suspicion, but he has no hint.… ...

TINA sees KWOK PING who shows much contented. She suspects he is the murderer of CHEONG SHAN. She even suspects that KWOK PING may kill her and worries all day. TINA wants the police protection. She tells PING ON that KWOK PING has planned to kill CHEONG SHAN in order to get the property. KWOK PING knows. He also accuses TINA has the intention to kill CHEONG SHAN too. The couple turn the cold shoulder. PING ON inquires TINA in a coffee shop. TINA meets the gigolo. TINA shows in a stranger manner. PING ON inquires further. He discovers that while CHEONG SHAN is being killed, TINA is with the gigolo to relieve her anguish. KWOK PING knows and loses his temper. LIN SUM is invited for inquiry. She tells the police that she is with TIN MAN while the murder is happened. TIN MAN knows LIN SUM has another intention. He does not question her. TIN MAN investigates LIN SUM secretly. He discovers that LIN SUM has got back her mother's bequest.… ...

PING ON recognizes the statement of LIN SUM has doubtful point. PING ON tells TIN MAN purposefully that he will arrest LIN SUM. He sees LIN SUM run away. He stops her at once and questions her. LIN SUM frankly admits that she has returned to the house to steal back the jade on that day. When she leaves, she finds CHEONG SHAN died. She flees away. PING ON believes her statement. PING ON casts off the family members who have the evidence that shows they are not in the house. There are only three persons left, LAI WAH, KWOK YEE and WING SHUN. He focuses to investigate them. TAI YAN attacks LAI WAH's statement that she has been with YEE and SHUN. He suspects that she is angry with CHEONG SHAN who presses KWOK CHUNG to divorce with her. She returns home and kills CHEONG SHAN. LAI WAH cannot explain. She appoints PING ON to explore. When PING ON nearly grasps the clues. YUK HING suddenly asks PING ON to accompany her to Macau.… ...

Under the investigation of PING ON, he knows LAI WAH has given a key to TIN MAN. TIN MAN gives the key to YUK HING mistakenly. When PING ON goes to find YUK HING, however, he cannot. PING ON guesses that YUK HING misjudges he and WAH rekindle their love relation. Due to her jealousy she leaves home. She meets an accident on the way. PING ON finds her everywhere. PING ON finds out unexpectedly that YUK HING and LEE FEI acquaint closely. The neighbours also spread rumour. He then suspects that they have adultery and questions LEE FEI. In fact, YUK HING comes from a 'theft family'. Her naked name is 'flying butterfly'. She lives together with her brother. LEE FEI, since their early childhood, they uses theft to earn their living. After she meets PING ON, they fall in love. As to avoid their identity influences their relationship, YUK HING decides to withdraw from theft. She marries PING ON.… ...

With the help of LEE FEI, PING ON finds the evidence which LAI WAH has hidden. Finally, he gets the exact evidence of arresting the murderer. The murderer is a member in the family. PING ON goes through a series of investigation and prediction. He finds LAI WAH and KWOK YEE have the same style swimming suit. It has been shown in front of people while the case happens. However, the time and place have been doubted. PING ON tests WING SHUN. WING SHUN admits she is the murderer without consideration. She even describes the process of killing. PING ON finds out many doubtful points. He vetos she is the murderer. PING ON sets up a trap. He forces the murderer to step in. Actually, who is the murderer? Why the murderer kills CHEONG SHAN and LAI WAH? Can PING ON arrests the murderer? After watching the finale, you will find the answers.