The ICAC investigates a case relating to a policy underwriter who has been suspected to trick thB company with some outsiders. In the case, HA, who is owns a travel agent, bribes KI WAN. HA arranges KI WAN to draw policies for four Filipinos. However the four men died several years ago. ~he beneficiaries are four companies. However all these companies close once they have received the money. ,HA and her boyfriend's joint account has over 1.2 million u. S. dollars. The ICAC suspect them as their income cannot explain the money. Through TSD, the ICAC records the conversation between HA and KT WAN. They get the warrant to search KI WAN's house. They find a large amount of money. KI WAN wants to stay away from the troubled water. He promises to assist the ICAC to gather evidence to prove HA guilty.

HA is a cunning 'woman and she is aware of plan of the ICAC. Therefore she manages to stay away from the trap. TOM is arrested in the Philippines and he is willing to act as the witness. Therefore the ICAC members apply for guns so arrest HA. After a life-risking chase and gun fight, YAN catches HA and saves the hostage LI. The ICAC transfers the information to the police in the Philippines. They continue to find HA's boyfriend B. B's gamble stalls and brothels are closed. He has no way to escape. He returns to Hong Kong. He threatens YAN with gas bombs and lurks her. The police arranges YAN to be protected in LI's house. From his informant, BILL finds B's place. There he finds LI's address.

B ties up the policemen who have been instructed to protect LI.YAN fights B and in chaos, CHEUNG (LI's step-father) is shot. Luckily the police force and ICAC arrive. B grasps the time to escape. . LI and YAN take refuge in a deserted house in a remote village. The police force send more people to protect them. B sends ON to see HA in the detention centre. Members of the ICAC and police force follow ON and at last, they arrest B in 'the bowling stadium.

YAN and LI go home. The case is reported by the television station. The public question whether the duty of the ICAC is dangerous or not. YAN's grandmother is angry when she knows that job nature of YAN. YAN tricked her that she is clerk but now she has to admit the truth. Her grandmother forces YAN to quit but at last she is convinced by YAN. However it is not the end. YAN's boyfriend is discontented. They break up after a severe quarrel. LI applies to work as a member of the ICAC. She is accepted and has to join a l0-week training course. BILL and YAN are tutors. In a practical session, LI is so careless that she nearly set a restaurant on fire.

After the training, LI is assigned to be supervised by YAN in Team B. The Immigration Department has recently arrested some illegal immigrants with fake documents. The ICAC investigate the case and they suspect that some senior officers have been bribed and the only clue is the informant called PING. With careful examination, the TSD finds that the chop on the fake documents carries the number 8533. However it is no longer valid. Now there are only five senior officers who can handle the chop. PING is being followed but he manages to escape for LI's carelessness. LIN comes across a poor couple. The husband is paralyzed and the wife has recently come from Mainland China to look after the husband. She is bearing a baby. LIN tries to help them by applying social security for them. She is shocked to see that the chop number is 8533 in the travel document.

LIN reports HUNG's case to the police. HUNG realizes that she has committed something illegal. She regrets but it is too late. She has to return to Mainland China. In order to stay with her husband so as to look after her husband, HUNG agrees to co-operate with the ICAC. She tells them that PING is the agent and she agrees to buy another travel document from PING so as to prove him guilty. The ICAC overhears PING's conversation with KI who works in the Immigration Department. However as the place is so noisy, they cannot record the conversation clearly. As it is an important chance, they arrest PING and arrange HUNG to contact KI. At last they manage to collect sufficient information and arrest KI.

PING and KI are found guilty in the court. They are imprisoned for three and four years respectively. HUNG gives birth to a boy but she still has to leave Hong Kong. Later the ICAC is appointed to investigate another difficult case. The department head of the credit card section of a bank reports that there are many bad debts which involve some clients who have never applied the credit cards of the bank. It is obvious that there are leaking holes in the bank operation and someone has used the information of the victims. Thus the ICAC starts investigating those shops and hotels which are related to the case.

After investigation, the ICAC discovers that the recent case is not done by those existing gangs. Later LAY finds a man who delivers leaflets. She suspects that the man has stolen the others' statements to apply credit cards. LAY informs her supervisor. The ICAC sends members to keep an eye on the man. it is found that the man is called STEPHEN. It is certain that STEPHEN works with a postman and there are some other people in his group. They lurk there to get the bill which has been thrown away by STEPHEN.

LAY and YAN's efforts are not in vain. At last they get the bills that they want. The ICAC wait for another chance to arrest the postman and STEPHEN. However STEPHEN is a cunning man and he manages to stay away from the troubled water. They can only question the postman' and accuse him being bribed. BILL learns from a loan shark than the postman had been in serious financial difficult but he paid all his debt suddenly. The postman knows that he cannot make any excuse and he promises to be a witness to accuse STEPHEN and his gang. The members of the ICAC use every means and ways to make STEPHEN admit what he has done.

The drugs section requests the ICAC to give a helping hand. The officers suspect that BOB the smuggler has bribed some officers and employed some air hostesses to carry drugs to Hong Kong. LIN and LAY pass the examination and they are instructed to work as spies. They are called JEN and ANGlE and move into Whampoa Sun Chuen. There they receive training and become air hostesses. They serve the route between Hong Kong and Vietnam. They become friends of MON and CHI. In a disco, they find that MON knows BOB. They tells MON that they are in financial difficulties. However MON arranges them to be prostitutes.

With MON's assistance, NAY and YAN go to a discotheque to find a man named SAM. However they are surprised to find that SAM is CHI. CHEUNG learns from HIN about NAY's job and goes to find her. For her duty, NAY scolds CHEUNG. The others do not suspect her. HIN meets NAY and YAN in air hostess costume. He spoils their plan by disclosing that they are working as spies. He promises not to tell the others. Instead he goes to the discotheque to protect them. NAY is impressed. NAY and YAN win BOB and CHI's trust. BOB and CHI visit their home suddenly and MING is there. MING clams that he is YAN's boyfriend. They go to dine together. YAN eats BOB's soft drugs and this makes BOB trust her.

LIN is instructed to keep an eye on BOB. BOB discovers her. YAN is so clever that she claims LIN as her sister who is a gambler. LIN is following him instead of BOB. BOB suspects them and goes to play mahjong in LIN's house. the ICAC set up a house to convince BOB. BOB is taken in. At last BOB is hooked. He asks NAY and YAN to smuggle drugs for him and he promises to give each of them fifty thousand dollars. However the company transfers NAY to another route and LIN replaces her. They follow BOB's instruction. They wear the pins and go through the number 4 gate. MING is ready to arrest them. NAY learns that it is a trick. She rushes to stop MING. MING changes the plan and waits for another opportunity.

After the case, Inspector C. K. of the Immigration Department is suspected. the ICAC secretly carry out investigation but get no further information. YAN, NAY and LIN decide to find more information in BOB's house. However BOB lusts for NAY's beauty. He drives her to the peak. Luckily HIN saves her. NAY finds a portable computer under the seat of BOB's car. they realize that BOB communicates with C.K. through computers. At last she gets C/K/'s information from BOB's computer. From the information, they find BOB's records of drug smuggling. Moreover they find that BOB has a sushi bar which proves that he has unknown income sources. BOB arranges the three girls to smuggle drugs for him but their plan is spoiled by the police. LIN is shot and her shoulder gets hurt.

MING blames the police and spreads the news that the police. received information about drug trade in BOB's mahjong house. LIN's condition is very bad. YAN calls MING who takes LIN to an illegal doctor. LIN is saved. At last all are as scheduled and all criminals are arrested. The three girls have finished their job and can go home to take a rest. MING and YAN fall in love with each other. HIN and LAY also become lovers. However LIN's family is endangered as her husband falls in love with the tutor YU. At last YU quits and LIN gives up her work so as to stay with her family. But it remains to be a black spot in her heart.

YAN meets her good friend CHEUNG again. CHEUNG has made brilliant success in the commercial field but he still misses YAN and wants to court her. CHEUNG hires TUNG and HIN of Yue Fung Finance to help his running of the company in the stock market. It is a success and in the banquet, CHEUNG jokes that he will compete with MING for YAN. HIN is promoted by CHEUNG. As there is an earthquake in the Philippines. Thinking that the hazard may affect the operation of the company, HIN makes .a survey which reveals that Shing Sai Company is a shell company. TUNG makes money through it.

The others also find problems relating to the balance sheet. Two accountants are sent from the headquarters to check it but both are killed. The police investigates the murder while HIN and TUNG are questioned by the ICAC. TUNG discusses with CHEUNG and CHEUNG threatens TUNG to help him finish the last debt or he will kill TUNG. Moreover CHEUNG also makes up all leaking holes of Tung Shing so that the ICAC can find no more information. CHEUNG registers Tung Shing Company with SIMON's name. Through it he borrows ten billion dollars to develop Century Villa. TUNG finishes his job and gives CHEUNG the disk containing information of the transaction. He leaves immediately and meets his wife in Canada. In fact he has hidden a copy of the disk in a soft toy.

CHEUNG has a plan and as he gets the disk, he kills TUNG and arranges the scene which shows that TUNG has committed suicide. HIN cannot stand it and tells the ICAC about the crime. The ICAC check TUNG and HIN's fortune. They find that TUNG own two blocks in Canada While there is no sign to show that HIN has been bribed. HIN interrupts the debt of Tung Shing Company. CHEUNG meets him and suggests to give him rewards. HIN pretends that he agrees and they are going to transact in the Golf Club. HIN informs the ICAC but CHEUNG gets wind of it and does not turn up. When CHEUNG wants to destroy the disk, he finds that TUNG has another copy and HIN has taken away all TUNG's belongings.

CHEUNG hires a killer to kill HIN and goes to HIN's house and office to take all disks. The ICAC is convinced by HIN and gives him protection. CHUNG gets CHEUNG's financial assistance to improve The Fire ?fighting device. However his mind is drowned by greed and he bribes the fire officer. He sends workers to work round the clock. There is a fire which causes a lot of damages. CHUNG returns to: Hong Kong. He argues with YAN and CHEUNG tries to settle the quarrel between them. With CHEUNG's help, CHUNG is released and YAN thanks him. However YAN is shocked to find TUNG's button on CHEUNG's sofa.

It is certain that CHEUNG is a critical person in the case. MING refuses to use the relationship between YAN and CHEUNG to get more information but YAN ignores MING's instruction and investigates the case. At last her presence in CHEUNG's office is recorded by CHEUNG's video recorder when she tries to check CHEUNG's computer. HIN is the next target. Three killers attack him and HIN is shot. He is seriously hurt. CHEUNG reports to the ICAC that YAN has blackmailed him. He gave CHUNG the money as instructed by her. He even opens a savings account for her in the bank in which he deposits a lot of money. He even informs the mass media.

The ICAC spreads the news that HIN has been killed. In fact HIN is kept in the headquarters of the ICAC. BILL tries to help YAN by finding LUNG to be the witness. However LUNG has been bribed by CHEUNG. YAN is accused and has to be brought to the court. BILL is angry and goes to beat LUNG up, hoping that LUNG will change his mind. However it is against the rule and thus he is dismissed. In the trial, LUNG changes his statements as he has been convinced by MING. YAN is released. Group B starts working. They discover that the signature of the savings account is a duplicate of the one on YAN's credit card. They also find the soft tot containing the disk. However CHEUNG has caught HIN and keeps him as the hostage. He threatens them to surrender the disk ...