FONG TSUN KIT, Chief Immigration Assistant of the Immigration Department, is monitoring the travelers with his good friend LEUNG CHI LUN at Lo Wu Control Point. KIT married mainlander CHEUNG SZ MAN long time ago and his son travels to Hong Kong to attend kindergarten everyday. KIT’s mother CHAN MEI PING was a widow and she married the grocery shop owner CHUNG KWOK SING later. KIT and SING’s son CHUNG CHI WING have no blood relationship but they treat each other like real brothers. MAN and her son are granted the right of abode in Hong Kong and they plan to move in to SING’s house. Coincidentally, WING’s wife CHIU LAI MAN is pregnant and they plan to move back to SING’s house as well in order to save money. A woman called WONG KWAI HO hurts her ankle while helping to catch a thief at Lo Wu Control Point. Afterwards, she finds that her identity card is lost and KIT asks her son to pick her up……

FONG TSUN KIT, Chief Immigration Assistant of the Immigration Department, is monitoring the travelers with his good friend LEUNG CHI LUN at Lo Wu Control Point. KIT married mainlander CHEUNG SZ MAN long time ago and his son travels to Hong Kong to attend kindergarten everyday. KIT’s mother CHAN MEI PING was a widow and she married the grocery shop owner CHUNG KWOK SING later. KIT and SING’s son CHUNG CHI WING have no blood relationship but they treat each other like real brothers. MAN and her son are granted the right of abode in Hong Kong and they plan to move in to SING’s house. Coincidentally, WING’s wife CHIU LAI MAN is pregnant and they plan to move back to SING’s house as well in order to save money. A woman called WONG KWAI HO hurts her ankle while helping to catch a thief at Lo Wu Control Point. Afterwards, she finds that her identity card is lost and KIT asks her son to pick her up……

KIT, YUE, KEI and LUN are good friends as well as colleagues of the same period. YUE moves to the Police Force and is promoted to Senior Inspector recently. He used to be KEI’s boyfriend and his current girlfriend is a teacher in a famous school. MING and FUNG’s father are old friends. Ever since FUNG’s father died, MING takes good care of FUNG and his family members. He treats FUNG like his own son and FUNG regards him as his role model. KEI is an independent and tough woman. She takes good care of her grandmother and gives full financial support to her younger sister ON YEE in pursuing tertiary education. YEE has got a daughter CICI without getting married and KEI treats CICI like her own daughter. KEI brings SZ MAN to renew her identity card. She discovers that LAI MAN treats SZ MAN like a servant and she reminds KIT about the situation……

KEI wants CICI to enter a famous school. She therefore goes to the police station to look for YUE because she wants YUE’s girlfriend to make referrals. YUE is questioning the new gang leader WU KIT SUM and he agrees to help KEI. Exchange student CHUNG CHI YAN is a good friend of YEE. After her mother died, YAN returns to Hong Kong. She meets AH WONG on the street and takes it home. FUNG asks KIT out on behalf of HO in order to thank him. During the time, the Immigration Department is arresting some illegal workers at the restaurant and the two of them help rescue a seriously injured illegal worker. Their action is highly appreciated and KIT's chance for promotion is increased. The Immigration Department wants to fight against illegal professional workers and MING's subordinates start working on the case. MING is invited to be one of the adjudicators in the promotion qualifying examinations……

KIT attends the interview and MING is one of the examiners. MING and KIT have bad relationship because KIT used to accuse MING for committing adultery with a female student long time ago. KIT lost the chance for promotion during that time. MING gives KIT tough questions again this time and KIT handles it calmly. HIM's PR firm has collaborated with a model agency which hires illegal workers and MING's subordinates arrest the illegal workers. HIM is also being investigated and he quarrels with MING about the case upon returning home. HIM is too angry that he moves to FUNG's home to stay temporarily. SZ MAN learns from the staffs that LAI MAN knew that those canned food has expired but she didn't remind her about it. She is also upset for KIT didn't try to protect her. YAN returns AH WON to SING but she runs away immediately after seeing him. WING follows YAN curiously and he is distracted after seeing her……

LAI MAN falsely accuses SZ MAN for causing the accident and she scolds her madly. KIT didn’t speak up for SZ MAN and she runs away angrily. SZ MAN goes to Mongkok alone and the gangster MA LAU tries to rape her. Fortunately, SUM rescues her because he had actually known her for a long time. KIT arrives to ask for SZ MAN’s mercy and they reconcile with each other. YEE is sick and KEI brings CICI to the school for interview. The headmaster tries to embarrass them since CICI comes from a single parent family. In order to protect CICI, KEI fights with the headmaster. LAI MAN returns from the hospital. Trying to improve the relationship with LAI MAN, KIT and SZ MAN deliberately change their room. WING meets up with YAN secretly for they are actually brother and sister. YEE meets up with FUNG to obtain some information. She makes use of FUNG to get rid of a pursuer and FUNG scolds her angrily……

HO asks MING to meet HIM at home but they start a quarrel again. MING takes HO's advice and he sells his beloved yacht for repaying HIM's debts. HIM is deeply touched and he reconciles with MING. KIT performs well in the examination and he is granted the chance for a second interview. LAU keeps calling SZ MAN to threaten her that he will disclose her past to everybody unless she gives him money. SZ MAN takes some money from the grocery shop to pay LAU. LAU thinks that the money is not enough and he asks SZ MAN to raise more money. SZ MAN meets SUM on the way and YUE witnesses it since he is following SUM. SZ MAN returns to claim that she has lost the grocery shop’s money on her way to the bank and LAI MAN scolds her angrily. KEI finds it suspicious and YUE questions KEI about SZ MAN's past. KEI and YUE follows SZ MAN and SUM separately. They end up going to the same building and LAU's dead body is discovered in a nearby location……

MAN suddenly moves back to Shenzhen without bringing HEI with her. WING always talks on the phone secretly and LAI MAN suspects that he is committing adultery. LAI MAN tails after WING with PING and they discover that he is meeting YAN. YAN hates PING for ruining her family and she refuses to get acquainted with her. SING visits YAN with his two sons but YAN treats them coldly. YAN's mother had actually divorced SING because she committed adultery. However, PING has taken all the blame in order to maintain the image of YAN's mother. KIT stops a suspicious person at Lo Wu Check Point and this person turns out to be the target suspect of MING again. The Investigation Unit and the Harbour Control Unit join hand together to fight against illegal immigration via cargo ships. While trying to investigate a cargo ship, the ship owner pushes the illegal immigrants to the sea nervously……

YUE threatens SZ MAN to frame SUM up but SZ MAN refuses to do so. WING discovers that SZ MAN used to work as a prostitute in Hong Kong. KIT fights with WING about this and SZ MAN leaves the home sadly for she doesn't want KIT to be embarrassed by her. SZ MAN meets KEI on the street and she reveals her tragic story of being cheated to become a prostitute long time ago. KIT overhears their conversation and he decides to forgive SZ MAN. YAN reveals her ambitions after graduation to FUNG and FUNG encourages her to join the Immigration Department. YEE discovers them talking happily and she later fights with FUNG for trivial things. KIT and SZ MAN have decided to start anew but rumors are all around. SZ MAN's case is even reported in the magazine in an exaggerating way and both of them feel very stressful. In order to minimize all the hassles, KIT decides to move to another place and transfer to another department……

KIT wants to start anew with SZ MAN but he cannot forget what she did in the past. He suspects that SZ MAN is committing adultery with SUM. He gets drunk and fights with SUM on the street. SUM sends KIT home and he meets WING. WING is upset and he quarrels with KIT about it. They end up fighting with each other and PING finds it unbearable. PING wants peace in the family so she persuades SZ MAN to leave. SZ MAN decides to go back to China and KEI asks KIT to stop her. KIT finds SZ MAN at the Control Point but he doesn't try hard enough to stop her from leaving. YAN and YEE go to the Immigration Department for interview at the same time coincidentally. After the interview, they meet FUNG and HO on the street. HO invites them to have BBQ at home and HIM also joins them. HO wants to match YAN and FUNG up so she voluntarily helps YAN find a place to stay……

The Investigation Unit successfully captures a perjury group but they fails to catch SUM. In order to carry out the arrest, MING fails to see WAI's father for the last time. KEI meets YUE on the street accidentally and they go to drink sweet soup together. The waiter believes that they are lovers and YUE's girlfriend misconceives that they have reunited with each other. YUE seizes the chance to propose a separation with her girlfriend. WAI is very ashamed that her father didn't die in peace because he failed to see MING. She wants a divorce and MING moves out of the house. MING learns from KIT's supervisor that KIT has separated with his wife. HEI is heart-broken after his mother left. He fights with his schoolmates and PING is injured in the chaos as well. HEI hates PING and KIT for forcing SZ MAN to leave. During the opening of New Shing Kei, HEI sneaks away secretly for he wants to look for his mother……

HO hopes to create chance for FUNG so she rents her rooftop area to YAN. FUNG performs well at work and he is transferred to the Investigation Unit. YAN and YEE get a job at the Immigration Department as well and HIM celebrates with the three of them. FUNG is not accustomed to the working environment and the colleagues at the Investigation Unit. MING treats him coldly at work deliberately. YUE helps KEI get rid of a nasty neighbour and KEI treats him dinner to thank him. After drinking, YUE reveals his love to KEI. KEI is shocked and she runs away immediately. In order to improve the relationship between KIT and HEI, KEI brings CICI to play with them. KEI also suggests KIT to join the Parents Day of HEI's school. KIT misses SZ MAN very much and he leaves voice messages to her all the time. WING delivers air-conditioner to YAN and SING tries to come with him but YAN refuses to see SING. FUNG discovers this accidentall

HIM helps reunite WAI and MING. However, the couple fights with each other again because of a woman's photo. This woman's name is MARY and WAI suspected that MING had committed adultery with her long time ago. MING talks with his subordinate HONG WING NIN and he discovers that MARY is NIN's younger sister. KIT learns from the traveler that trust and respect are the key elements in maintaining a relationship. He tries to apply this to HEI and HEI finally lets go of the past. SUM's enemy TUNG provides information to YUE for attacking SUM. KEI is very angry for nobody remembers her birthday. When she returns home, she discovers that YUE has been waiting for her and she decides to accept his love once again. While MING is observing SUM's perjury group, YUE suddenly arrives and starts a gunfight with the group. During the chaos, SUM sneaks away as if he had already known that somebody would come……

KIT discovers that SZ MAN has listened to his voice messages. He hopes that she will join HEI's Parents Day but she doesn't show up. KIT is depressed and KIT consoles him. FUNG performs well at work and he develops a good working relationship with the team. MING appreciates it very much. MING and WAI are divorced eventually and HIM is very sad about it. YAN and YEE join the training camp together. PING delivers daily commodities to YAN on behalf of SING. LUN indulges in gambling and he even borrows money from his colleagues. An informer of the Immigration Department is killed in a car accident and YUE believes that this is done by SUM. MING scolds YUE for indirectly killing the informer but YUE fights back by saying that his way of doing things is old-fashioned. YUE decides to focus on attacking SUM and he lets go of many other gangsters. TUNG hints to YUE that he will attack SUM and YUE doesn't express any opinion……

KIT repays the debt for LUN and he wants LUN to stop gambling. KIT decides to stop leaving voice messages to SZ MAN and starts anew. YUE brings KEI to a gathering with his boss. He tries to use flattering speech to please his boss. On the other hand, KEI feels that she has communication gap with the boss’ wife and she decides to pursue further studies. FUNG meets YEE at the pub and he misconceives that she is selling her body but YEE is actually selling insurance plan. FUNG discovers from the MP3 that YEE loves her daughter very much and he changes his perception on her slightly. LAI MAN enters the hospital to give birth. YAN rushes to the hospital to take photos for the baby. YAN and YEE are assigned to Lo Wu Control Point after completing the training. On her first working day, YAN is captured by somebody who had been rejected to enter the territory……

After seeing the baby, YAN discovers that SING is looking at her uniform photos. During KEI’s first day of work at the Prosecution Section, KENNY asks her to go to the court since her colleague is sick. KEI forgets to bring a document and KENNY scolds her in front of everybody. KIT's outstanding performance is widely discussed on the Internet. MING wants to transfer him to the Investigation Unit but NIN doesn't agree with him. FUNG carries out investigation on a new immigrant LI YUET NGOR. He discovers that NGOR is chasing a man called LO KAI SANG for a letter of credit and he suspects that NGOR is arranging bogus marriage for others. KIT finds that MING is repairing his car on the street and he tries to help him. MING claims that KIT is worse than an old car. KIT cannot bear the insult and he agrees to take the challenge of transferring to the Investigation Unit……

KIT's colleagues discover that KIT used to be MING's student. They believe that KIT has close relationship with MING so they put him on their guard. During KIT's first investigation task, his colleagues ask him to wait in the car. He discovers a suspicious Indian or Pakistani and this man passes by with a chemical product’s plastic bag. KIT raises his suspicion during a meeting but NIN doesn't agree with his viewpoint. YUE invites KEI for lunch. KEI is surprised to find that WAN Sir and his family are there as well. They keep discussing about their future and further studies plan during the gathering. KEI feels stressful with it. SANG rushes to the Marriage Registry to register for marriage and FUNG follows him secretly. FUNG tries to arrest them when NGOR gives SANG money but he is discouraged after realizing that this is not a bogus marriage……

MING suddenly feels unwell while trying to catch the man who shot YUEN. The case is assigned to YUE for follow-up actions. MING blames KIT for failing to hold on with what he was suspecting in the beginning. MING thinks that MING is the one who caused YUEN's injury and he wants KIT to leave the Investigation Unit. LUN discovers a suspicious mainland visitor. FUNG carries out investigation on him and he successfully arrests NGOR. KIT wants to transfer to another department but his mind changes after learning that FUNG has successfully arrest the key person who arranges bogus marriages. KIT declares to MING that he is determined to stay in the unit. YUE discovers some important hints of the hotel murder case from KIT and he checks out KEI's file secretly to look for information. KEI discovers an illegal worker without any identity and she asks the Investigation Unit to help……

HIM reveals his love to YEE and FUNG witnesses this accidentally. MING's vision becomes blurry suddenly while driving. KIT is besides him and gets him safe away from a car accident. FUNG suspects that YEE's maid is doing part-time job in a pub and he informed HIM about it. FUNG goes to BBQ with YEE, YAN and HIM. FUNG is unhappy to see that YEE and HIM are acting intimately. Meanwhile, YEE teases YAN for paying special attention on FUNG. KIT discovers that LUN is selling his car and he suspects that LUN starts gambling again. LUN explains that his grandfather needs money for an urgent operation. An unconscious man with some wound on his hand is discovered in the walled village. KIT suspects that this man is related to the illegal worker case in the walled village. YEE feels stressful after knowing that HIM's father is MING and his mother is a famous woman in town……

MING's disease is getting serious and the doctor urges him to have operation but MING hesitates. During a meeting at the Investigation Unit, NIN suggests that they should wait and catch the head of the gang but MING insists to carry out the arrest as soon as possible. During the arrest, MING feels unwell again. The leader of the illegal workers drives over a worker while trying to escape. MING chases after him madly. KIT and FUNG find MING acting strangely these days and they question him. MING finally reveals that he has got a brain tumor. After applying for sick leave, MING rushes to the opening ceremony of WAI and NAM's photo exhibition but his suddenly feels unwell again. WAI is upset for MING’s absence and she agrees to go to South Africa with NAM. MING's condition is getting worse and he agrees to have operation immediately. FUNG asks WAI and HIM to support MING at the hospital. MING's operation turns out to be successful……

WAN Sir starts investigating a case on illegal workers and he believes that the gang leader TUNG is involved in the case. YUE visits TUNG and TUNG tries to bribe him. HONG SUK CHING asks KIT, KEI and LUN out for a reunion gathering. CHING is the younger sister of NIN and she suddenly leaves Hong Kong long time ago after being hurt by MING. NIN waits for CHING at the hotel and he reminds her to take medicine. After leaving the hospital, MING stays at HO's home. HO tries to reunite MING and WAI. However, WAI cannot forgive MING for committing adultery with CHING long time ago. YAN discovers that her blood type is different from SING and WING. She suspects that she is not SING's real daughter. SING buys a flat for YAN but YAN doesn't want to accept it for she is not his real daughter. FUNG and HO try to console YAN by persuading her to let it be. CHING questions WAI for MING's address and she talks to her in a bad manner……

The police discover a lot of illegal workers in a container truck at Ma Liu Shui. WAN Sir believes that TUNG is involved in it. YUE warns TUNG to stop doing it but TUNG threatens him with a video showing that YUE had accepted a gold watch from him. YUE gives information of illegal workers to NIN deliberately. When NIN carries out the arrest, YUE carries out investigation at TUNG's club as well to look for the video. NIN discovers some drugs and a gun in TUNG's car. TUNG seizes the gun and runs away. KIT learns from WING that YUE has gone to TUNG's place for investigation and he finds it suspicious. TUNG discovers that SHUI is acting intimately with a man on the street and he scolds SHUI immediately. SHUI is upset and she moves to her classmate's home to stay. CHING asks KIT to give her MING's address. Upon seeing MING, CHING becomes mad. During the chaos, CHING captures WAI with a knife……

YAN discovers that SHUI is going to Shenzhen. WAN Sir and VINCY ask YUE out for dinner. MING assigns KIT and KA to handle a case with the Customs and Excise Department. They successfully capture seven smugglers and find a girl called SUET YEE at the drains. SHUI appears at Lo Wu Control Point in untidy clothes. YEE brings her home. FUNG is enraged and he rushes to YEE's place to take SHUI home but YEE scolds him angrily. FUNG cares about her sister alot and he persuades YAN to take good care of SING. FUNG apologizes to YEE. HIM arrives to find that FUNG and YEE are talking happily. Together with a staff from the Social Welfare Department, KIT brings SUET YEE back to her father's place. They finds SUET YEE's mother CHU in the house and CHU has been overstaying in Hong Kong for a while already. KIT and KEI prepare documents for CHU overnight in order to arrange special permit for her to stay longer in Hong Kong……

FUNG invites YEE to home for hot pot. HIM is upset to find that FUNG and YEE are talking happily. HIM invites YEE to a special place for dinner but he actually wants to show YEE to his parents. YEE is upset. CHEUNG invites YAN to a classical music concert. YEE seizes the tickets and persuades YAN to go with FUNG. FUNG reminds HIM to take things slowly. WAI encourages HIM to apologize to YEE as soon as possible. HIM visits YEE with flowers but he finds FUNG in YEE's place. HIM waits for FUNG outside and he accuses FUNG for trying to step in between him and YEE. YAN visits SING with some medicated oil and she accidentally overhears that SING is going to look for KEUNG. On the next day, YAN sees KEUNG at the train station. KEI prepares a cake for YUE and she asks for KIT’s company in visiting YUE……

SZ MAN wants a divorce but KEI persuades KIT to reunite with SZ MAN. KIT visits SZ MAN at her flower shop but he is shocked to find SUM there. MING recommends KIT to take the promotion qualifying exams. He also transfers NIN to another unit and NIN is dissatisfied. SUM waits for NIN outside his office for he wants to bribe him so as to stop NIN's team from fighting against them. SING arranges a meeting between YAN and KEUNG. YAN unmasks KEUNG instantly. FUNG encourages YAN to cherish her relationship with SING's family. He also persuades her to forgive her father. FUNG asks SHUI to send the video to HIM. HIM is being scolded for making mistakes and he resigns angrily. SHUI finds that HIM is drunk and she brings him home. While trying to console HIM, SHUI ends up sleeping with him. KEI brings SZ MAN to see KIT and HEI. KIT believes that SZ MAN still cares about him but SZ MAN reminds him to sign the divorce agreement……

KIT visits SZ MAN right after taking the promotion qualifying exams and he reveals that he will not give her up. MING arranges manpower for the next project and NIN doesn't get any important duty. KA discovers that NIN is sending SMS before going for the arrest and NIN stuns him. MING and his team arrive at a village house. NIN waits for SUM at the pub and ICAC arrests SUM for bribing NIN. MING transfers NIN to another unit and recommends his promotion. During dinner, LUN points out that KEI doesn't treat KIT as pure friend. SHUI treats HIM as her boyfriend but HIM reveals that he only treats her as his younger sister. SHUI tries to commit suicide and she reveals to FUNG about what happened between her and HIM. FUNG is enraged and he rushes to HIM for explanations. HIM's friend invites him to open a pub together. FUNG arrives to fight with HIM. KIT visits SZ MAN and he meets SUM. SUM hits KIT angrily and SZ MAN doesn't stop him……

SZ MAN reveals to KEI that she truly loves SUM. LUN discovers that YUE is withdrawing large amount of money from the bank. He follows him and discovers that YUE is giving TUNG the money. LUN wants to report this to the police but YUE reveals to LUN that TUNG has been threatening him with a video. LUN agrees to help raise money for him. YUE drives LUN to meet up with KEI. They both persuade KEI to stop investing on a hopeless relationship. KIT passes the promotion qualifying exams and he goes home to celebrate with family members. Everybody tries to find ways to reunite KIT and SZ MAN. YEE picks up a fake HKSAR passport at the Control Point. She sends it to the Investigation Unit and KIT is assigned to handle the case. SHUI decides to move out and FUNG doesn't stop her. HIM wants to stop drug trading in his pub but his partner stops him. In order to prove to MING that he can earn lots of money, HIM finally compromises……

PING and SING invite SZ MAN home for a birthday celebration with LAI MAN but SZ MAN rejects them. LUN borrows money for YUE and he accompanies YUE to meet TUNG. TUNG discovers that some of the cash are counterfeit money and he fights with them. During the chaos, somebody hits LUN's head. WING is shocked to discover that LUN and TUNG are seriously injured at an industrial area. KIT loses his wedding ring and he goes to the garbage room to search for it. SZ MAN discovers KIT's ring in the car. SZ MAN tells SUM about it and SUM asks her to return it to KIT. WING informs KIT that LUN is seriously injured. YUE comes to the hospital after an investigation at the industrial area. KEI says that she hears YUE's voice when talking to LUN on the phone before his injury but YUE denies. WING discovers that YUE is highly sensitive with all evidence of the case. KEI is very angry for the newspaper is saying bad things about LUN……

WING finds that YUE is looking for something from the items collected at the crime scene. The doctor says that LUN may be able to wake up soon and YUE is worried. When FUNG carries out investigation at HIM's pub, SHUI suddenly collapses and vomits foam. The ICAC invites MING for an investigation on HIM's work at the pub. SUM claims that MING is receiving money from him through HIM. KIT, WING and HO help move the furniture for SZ MAN. KIT and KEI discover that a creditor is visiting LUN's house for money. The creditor claims that LUN has borrowed 100 thousand dollars from him to help his good friend. KIT and KEI believe that this friend is YUE. WING discovers a videodisc at the crime scene and YUE is very nervous. WING gives the videodisc to SZ MAN secretly and he asks SZ MAN to give this disc to KIT. YUE suspects that WING has given the videodisc to SZ MAN and he rushes to her place……

KEI suddenly stands in front of YUE to scold him. At the same time, WING stops KIT from pointing his gun to YUE. HIM visits SUM and he asks him to let go of MING. He hits SUM's subordinates accidentally and SUM reports it to the police. HIM runs away and he meets FUNG. FUNG persuades him to surrender to the police but HIM refuses. MING brings food to the yacht to look for HIM. He persuades HIM to surrender himself to the police and HIM finally agrees. YEE discovers that a person called SAM is using fake identification and she asks YAN to follow him. FUNG and KA lead the team to arrest SAM successfully. SAM refuses to provide any information but KIT convinces him eventually. KIT and YUE join hand together to arrest SUM. YUE is determined to kill SUM and they start a gunfight. SUM captures KIT and he drives away. YUE follows them to an empty factory. SUM persuades KIT to kill YUE in order to take revenge for SZ MAN……