Undercover police agents lead double lives, until they discover that a mole has been inside the police force. Their world is about to crumble.
S01:E01 - Line Walker
DING SIU-KA and her three foster mothers operate a foot spa together. She is also an undercover officer working for CIB chief inspector HONG TO-HANG. CHEUK HOI is TO-HANG's colleague. He is suspected of corruption and the ICAC is carrying out investigation on him. CHEUK HOI tries hard to find the dead body of his undercover officer and he swears that he will not let another undercover officer die. When he returns to the police station, chief inspector from the Organized Crime and Triad Bureau (OCTB) YIP SHIU-LEUNG provokes him. SIT KA-KEUNG appears to be an ice delivery worker but he is actually a member of an illegal betting syndicate. SIU-KA's foster mother is in debt and KA-KEUNG arrives to make trouble at their foot spa. SIU-KA tries to get the cash and the receipt for borrowed money from KA-KEUNG but KA-KEUNG discovers it. YAU TAT-FU, nickname Flounder, is a triad leader. His subordinate KA-KEUNG has helped him to hide away his criminal evidence accidentally and the police fail to charge him successfully. Besides getting the receipt for borrowed money from KA-KEUNG, SIU-KA discovers the criminal evidence of TAT-FU as well. CHEUK HOI discovers TO-HANG falling down from a building suddenly and TO-HANG dies. As instructed by TO-HANG, CHEUK HOI decides to locate the undercover officers working for TO-HANG so that he could find out the truth behind his death.
S01:E02 - Line Walker
KA-KEUNG is released. He immediately goes to the foot spa with his subordinate CHEUNG MUK-WING for he wants to get back the account record and name list from SIU-KA. TAT-FU praises KA-KEUNG and KA-KEUNG requests to be the person in charge of his illegal betting business. CHEUK HOI wants to get some important information from TO-HANG's computer but he doesn't have the password. KA-KEUNG tries to fight for the right to handle the illegal betting business and he is being chased. SIU-KA is embroiled in it as well. TAT-FU tries to mediate between the two groups and he suggests choosing the person in charge based on their profits. In order to find TO-HANG's undercover officers, CHEUK HOI attends his funeral. SIU-KA attends the funeral secretly and CHEUK HOI discovers her. SIU-KA passes CHEUK HOI's test and she becomes his undercover officer. SIU-KA learns that TO-HANG was carrying out investigation on the illegal betting syndicate before his death and she decides to approach KA-KEUNG for more information...
S01:E03 - Line Walker
MUK-WING is being cheated during betting. He tries to get back the money from his enemy but he is captured. Luckily, SIU-KA knew that KA-KEUNG will be in danger and she goes to rescue them. HO-KAN and FOON-HEI get to know each other in the prison. FOON-HEI is very upset to discover some prisoners trying to operate usury in the prison and HO-KAN tackles the problem. FOON-HEI is very pleased and he promises to offer works to him later. When TAK-FU tries to announce the result for operating the illegal betting business, SIU-KA arrives to help KA-KEUNG and KA-KEUNG wins eventually. SHIU-LEUNG tries to carry out investigation on the illegal betting syndicate but CHEUK HOI is not willing to cooperate with him. SHIU-LEUNG decides to get information from SIU-KA. HO-KAN is released from prison eventually and he starts working in a stock agency but two gangsters suddenly arrive to capture him. FOON-HEI appreciates HO-KAN's talent very much and he wants HO-KAN to work for him...
S01:E04 - Line Walker
KA-KEUNG is invited by TAT-FU to attend a triad organization's banquet. As instructed by CHEUK HOI, SIU-KA brings a hidden camera with her to collect information but the camera is not working properly. FOON-HEI discovers HO-KAN giving his spoiled son a lesson and he asks HO-KAN to help managing his son. When HO-KAN returns home alone, he meets his ex-girlfriend SIN-YAN but SIN-YAN refuses to have contact with him. TAT-FU wants to be the triad leader and he asks his subordinates to kidnap FOON-HEI's only son. Both FOON-HEI's son and HO-KAN are being kidnapped. FOON-HEI's son is injured and he keeps bleeding. KA-KEUNG asks SIU-KA to help finding a doctor to treat him at the hiding place. SIU-KA informs CHEUK HOI immediately and CHEUK HOI gives SIU-KA a tracking device...
S01:E05 - Line Walker
CHEUK HOI bursts into the hiding place with his subordinates but they fail to find SIU-KA and the others. CHEUK HOI discovers the whereabouts of FOON-HEI's son successfully based on the clues left by SIU-KA. TAT-FU calls his subordinates and asks them to kill FOON-HEI's son. SIU-KA tries to stop them and HO-KAN seizes the chance to make trouble as well. CHEUK HOI bursts into the place and they start a gunfight. During the chaos, KA-KEUNG and MUK-WING take FOON-HEI's son away. KA-KEUNG is being punished by TAT-FU for taking FOON-HEI's son away without informing him. SIU-KA believes that HO-KAN is TO-HANG's undercover officer as well. She sneaks into the hospital to look for him. However, she discovers FOON-HEI arriving to visit HO-KAN. HO-KAN finally reveals his real identity to SIU-KA and CHEUK HOI. In order to find the truth behind TO-HANG's death, the three of them decide to continue their investigation on FOON-HEI and TAT-FU. Being an officer at the ICAC, SIN-YAN still suspects that CHEUK HOI is involved in corruption.
S01:E06 - Line Walker
SIN-YAN suspects that CHEUK HOI is bribed by FOON-HEI and CHEUK HOI tries not to disclose the truth to her. FOON-HEI visits SIU-KA's foot spa on the election day for the gang leader. He then asks SIU-KA to be his spokesperson in a meeting with TAT-FU. FOON-HEI meets up with TAT-FU alone and he lures him to gain money from the stock market together. HO-KAN and SIN-YAN were lovers. In order to carry out his duty, HO-KAN has committed crime. SIN-YAN didn't know the truth behind and she decided to separate with him. HO-KAN helps TAT-FU to earn a lot of money within a short period of time. TAT-FU worries that FOON-HEI will harm him after knowing that he has kidnapped his son before. He tries to shift the blame to KA-KEUNG and he beats KA-KEUNG fiercely. SIU-KA brings KA-KEUNG to her foot spa for a rest and she makes excuse to gamble with him but she loses eventually.
S01:E07 - Line Walker
SIU-KA loses a lot of money and she tries to take the money back by making KA-KEUNG drunk. However, she is drunk as well eventually. They end up sleeping together and SIU-KA's foster mother discovers it. SIU-KA has no choice but to claim that KA-KEUNG is her boyfriend. After breaking up with HO-KAN, SIN-YAN starts dating with SHIU-LEUNG. In order to gain trust from TAT-FU, HO-KAN goes to the night club with him but he meets SIN-YAN accidentally. In order to disturb FOON-HEI's illegal betting business, TAT-FU asks somebody to inform the police secretly. SHIU-LEUNG captures the whole team but he is not able to find any evidence against FOON-HEI. On the other hand, TAT-FU loses a lot of money from investments and the police is looking for him. The senior management of ICAC decides to suspend the investigation on CHEUK HOI but SIN-YAN tries to monitor CHEUK HOI even harder. CHEUK HOI tries to learn about SIN-YAN's family life by using eavesdropping device secretly. He discovers that SIN-YAN's elder sister SIN-CHING is beaten up by her husband WING-KUEN all the time.
S01:E08 - Line Walker
In order to capture TAT-FU, CHEUK HOI carries out investigation at the warehouse and he is embroiled in a gangster fight accidentally. In order to rescue TAT-FU, KA-KEUNG fights against the gangsters with CHEUK HOI. FOON-HEI has established an unassailable position in the gang. He wants HO-KAN and KA-KEUNG to collaborate with each other. CHEUK HOI investigates the clues left by TAT-FU and he has new findings. FOON-HEI organizes a banquet for KA-KEUNG and other subordinates. SHIU-LEUNG suddenly arrives with a group of police officers and he brings SIN-YAN to HO-KAN deliberately. Senior management of ICAC asks SIN-YAN to stop her investigation on CHEUK HOI. SIN-YAN tries to air her grievances to SHIU-LEUNG and SHIU-LEUNG proposes marriage to her. SIU-KA's foster mother worries that KA-KEUNG will make SIU-KA die and she asks KA-KEUNG to separate with her. SIU-KA tries hard to speak for KA-KEUNG. KA-KEUNG and SIU-KA return to work at their secret office. Some gangsters suddenly arrive to make trouble.
S01:E09 - Line Walker
KA-KEUNG is beaten up by the gangsters fiercely and he believes that they are FOON-HEI's subordinates. KA-KEUNG and SIU-KA go to question FOON-HEI but FOON-HEI's subordinates try to make things difficult. SIN-CHING is beaten up by her husband WING-KUEN regularly but she tries to be forbearing all the time. In order to help SIN-CHING, CHEUK HOI becomes the instructor of her interest class. He follows SIN-CHING home secretly and discovers that she is beaten up by WING-KUEN again. SHIU-LEUNG and SIN-YAN start making preparations for their wedding. HO-KAN is heartbroken and he decides to stop working as an undercover officer. FOON-HEI wants to get involved in Hong Kong's drug market but the drug trafficker is not cooperative. FOON-HEI asks KA-KEUNG to steal the drugs from the drug trafficker's kennel. SIU-KA follows KA-KEUNG secretly and she meets HO-KAN. KA-KEUNG and SIU-KA are pretending to be lovers only. However, their relationship is getting closer and closer and SIU-KA's family members begin to accept KA-KEUNG.
S01:E10 - Line Walker
The drug trafficker who refused to collaborate with FOON-HEI is being killed in the detention house. FOON-HEI gains full control of Hong Kong's drug market successfully. FOON-HEI appreciates KA-KEUNG and he asks him to handle the drug trafficking business for him. SIN-YAN accidentally discovers the eavesdropping device from CHEUK HOI. On the other hand, CHEUK HOI invites SIU-KA to meet up for information exchange. In order to get rid of SIN-YAN, CHEUK HOI runs away with SIU-KA by car. SIU-KA learns that CHEUK HOI is being investigated by the ICAC. Together with HO-KAN, they try to find out if CHEUK HOI is trustworthy. FOON-HEI asks KA-KEUNG to meet up with the overseas drug trafficker in the hotel. SIU-KA accompanies KA-KEUNG to the hotel and the drug trafficker asks SIU-KA to taste the drugs. In order to protect SIU-KA, KA-KEUNG tastes the drugs instead. The transaction is successful but KA-KEUNG is dying.
S01:E11 - Line Walker
SIN-YAN is not allowed to continue her investigation on CHEUK HOI. She has no choice but to carry out investigation on HO-KAN instead. CHEUK HOI teaches SIN-CHING to cook for her husband who is staying in the hospital but WING-KUEN doesn't appreciate it at all. HO-KAN meets up with KA-KEUNG and SIU-KA at FOON-HEI's place. He discovers that FOON-HEI is planning to traffic a large amount of drugs. In order to get HO-KAN's criminal evidence, SIN-YAN visits him at his place and she tries to steal information from his computer secretly. FOON-HEI makes plan for his drug trafficking business. He asks KA-KEUNG, SIU-KA, MUK-WING, HO-KAN and the others to wait at the shopping centre. MUK-WING makes a mistake and HO-KAN seizes the chance to inform CHEUK HOI about FOON-HEI's plan. On the other hand, when SIU-KA tries to inform CHEUK HOI, FOON-HEI's subordinate discovers it.
S01:E12 - Line Walker
SIU-KA is beaten up by FOON-HEI's subordinate and HO-KAN arrives to stop it. KA-KEUNG arrives to help as well. KA-KEUNG and SIU-KA try deceive FOON-HEI by acting in front of him. HO-KAN returns to the hotel to meet up with FOON-HEI and the others. In order to gain trust from FOON-HEI, he pretends that he is being chased by the police. Since FOON-HEI has cancelled his plan, the drug dealer ON LAM returns to her hiding place to meet up with the one behind the scene, SHUNG KAM. SHUNG KAM and FOON-HEI used to be partners. However, FOON-HEI has betrayed SHUNG KAM and SHUNG KAM wants him to die. MUK-WING suddenly borrows money from KA-KEUNG. SIU-KA and KA-KEUNG follow him and they discover the truth. WING-KUEN leaves the hospital. He suddenly treats SIN-CHING kindly and he tries to borrow money from her. With MEI-YIN's help, CHEUK HOI monitors WING-KUEN with eavesdropping device and he discovers that WING-KUEN has deceived SIN-CHING.
S01:E13 - Line Walker
Being cheated by WING-KUEN, SIN-CHING loses her home and savings. However, she blames CHEUK HOI for unmasking WING-KUEN. In order to carry out investigation, SIN-YAN keeps meeting up with HO-KAN and SHIU-LEUNG is jealous. KA-KEUNG passes his valet parking business to MUK-WING so that he will not participate in FOON-HEI's drug trafficking matters. FOON-HEI meets up with ON LAM. KA-KEUNG is the driver and ON LAM is interested in him. SIU-KA is very jealous. SIN-YAN discovers that SIN-CHING has no place to stay and she invites her to stay in her place temporarily. SHIU-LEUNG throws away the lighting decorations that represent their past memory. SIN-YAN tries to search for it at the dump. After knowing it, HO-KAN sends his lighting decoration to SIN-YAN but SIN-YAN doesn't appreciate it at all. SIN-YAN returns home and discovers that WING-KUEN has arrived to beat SIN-CHING. SIN-YAN fights with WING-KUEN and she collapses.
S01:E14 - Line Walker
WING-KUEN has come to a dead end and he decides to kill SIN-CHING by gas leak. CHEUK HOI arrives at SIN-YAN's home coincidentally and he rescues them with HO-KAN. WING-KUEN tries to run away by abducting SIN-CHING to a car and CHEUK HOI chases after them madly. HO-KAN and SIN-YAN are caught in the gas explosion. FOON-HEI's son LONG-SING has started a fight with others and the teacher invites FOON-HEI to meet up. LONG-SING has started a fight with other classmates because they say that FOON-HEI is a gangster from the triad society. FOON-HEI visits SIU-KA's foot spa and all the foster mothers are overjoyed. They are surprised to discover that all of them are interested in FOON-HEI. SIN-YAN is absentminded all the time after the explosion. SHIU-LEUNG is very jealous and he decides to fight against HO-KAN. KA-KEUNG discovers that other gangsters are invading MUK-WING's territory. In order to enhance MUK-WING's self-confidence, KA-KEUNG and SIU-KA support MUK-WING to get back his territory.
S01:E15 - Line Walker
After getting information from all the undercover officers, CHEUK HOI decides to arrest FOON-HEI and the others when they are trafficking drugs. However, when they are carrying out their duty, SHIU-LEUNG suddenly arrives with a group of police officers to monitor them. FOON-HEI asks SIU-KA and KA-KEUNG to go to the countryside with ON LAM for drug trafficking while he greets the buyer with HO-KAN and the other subordinates. When KA-KEUNG and the others arrive, they are being attacked. SHUNG KAM has arranged everything for he wants to get FOON-HEI's drugs and money at the same time. After knowing the truth, FOON-HEI decides to retaliate. In order to rescue SIU-KA, KA-KEUNG is injured and he is being abducted as well. SIU-KA wants to rescue KA-KEUNG and she decides to ignore CHEUK HOI's order. With her body wrapped in explosives, she visits ON LAM alone with all the drugs.
S01:E16 - Line Walker
FOON-HEI's son has died and he is very angry. He tries to vent his anger by attacking the traitors in the organization. CHEUK HOI meets up with all the undercover officers. HO-KAN cannot bear it anymore. He reveals his dissatisfaction and he wants to quit the job. HO-KAN meets up with SIN-YAN. SIN-YAN tells him a secret and HO-KAN is deeply shocked. HO-KAN is missing suddenly and he takes away all the money from FOON-HEI. FOON-HEI asks his subordinates to chase after HO-KAN. KA-KEUNG informs CHEUK HOI about it. CHEUK HOI discovers HO-KAN's whereabouts and HO-KAN is trying to commit suicide. Encouraged by CHEUK HOI, SIN-CHING returns to work at the law firm she used to stay before but a child abuse case is troubling her. The police is searching for FOON-HEI since he has made great troubles in town and FOON-HEI is not able to attend his son's funeral. SIU-KA is softhearted and she brings FOON-HEI to the funeral parlor secretly.
S01:E17 - Line Walker
SIN-YAN and SHIU-LEUNG will be getting married soon but SIN-YAN discovers that SHIU-LEUNG is hiding something away from her. With continued efforts, SIN-CHING finally helps the victim to win the case successfully. In order to thank CHEUK HOI for his support, she invites him to meet up at the cookery workshop. CHEUK HOI starts carrying out investigation on SHIU-LEUNG's background but the headquarters have asked SHIU-LEUNG to take up TO-HANG's post. SIN-YAN is caught in a car accident and she is sent to the hospital. She uses her injury as an excuse to postpone her wedding date with SHIU-LEUNG. ON-YEE discovers that SIN-YAN is worrying and she promises to help investigating SHIU-LEUNG. When HO-KAN is at work, some tyrants from the New Territories arrive. HO-KAN is not able to find FOON-HEI and he tries to contact KA-KEUNG. SIU-KA finds FOON-HEI according to KA-KEUNG's instructions. She discovers that FOON-HEI is very depressed and she brings him to the foot spa to meet up with her foster mothers. SIU-KA rushes to the night club and she discovers the relationship between FOON-HEI and the tyrants.
S01:E18 - Line Walker
On the way home, SIU-KA is drunk and she seizes the chance to declare her love to KA-KEUNG. SIN-CHING meets up with CHEUK HOI frequently and their relationship is getting very close. The tycoon SUNG YIN-TING parks his car at MUK-WING's territory and his car is robbed. MUK-WING helps him to find the stolen items successfully and YIN-TING appreciates it very much. MEI-YIN is missing after following somebody but SHIU-LEUNG is not trying to find her. When CHEUK HOI and the others are working, SHIU-LEUNG suddenly arrives at the hiding place of SIU-KA and the other undercover officers with a group of armed police officers. FOON-HEI's boss urges him to handle the land resumption project at Northeast New Territories. FOON-HEI asks SIU-KA and the others to meet up with the tyrants from New Territories together. ON-YEE returns home and discovers that TO-HANG's gift is missing. The cookery workshop is believed to be taken over by violence and SIN-CHING takes the case for the workshop but the witness change the mind suddenly.
S01:E19 - Line Walker
In order to get some evidences, CHEUK HOI sneaks into the hotel to carry out eavesdropping but he is discovered by others. Trying to hide away from the chasers, CHEUK HOI sneaks into a dance party with SIN-CHING. CHEUK HOI invites the undercover officers to meet up but he fails to see ON-YEE. He is worried and he carries out investigation on SHIU-LEUNG secretly. With everyone's efforts, they finally discover the whereabouts of ON-YEE. KA-KEUNG and the others want to take revenge for ON-YEE by attacking SHIU-LEUNG but CHEUK HOI stops them. CHEUK HOI scolds KA-KEUNG. SIU-KA is worried about KA-KEUNG and she cannot bear to reveal her feelings to him. SIN-YAN discovers that SHIU-LEUNG is the spy in the police force. She wants to report it to the police but SHIU-LEUNG discovers it and they start a fight. SIN-YAN tries to run away but she is captured by SHIU-LEUNG eventually. Luckily, HO-KAN passes by for he is worrying about SIN-YAN. In order to rescue SIN-YAN, he starts a fight with SHIU-LEUNG.
S01:E20 - Line Walker
In order to rescue SIN-YAN, HO-KAN falls down from a building with SHIU-LEUNG and he loses his consciousness. SIN-YAN goes to HO-KAN's home to tidy up the place and she discovers his secret journal. CHEUK HOI arrives to reveal everything to SIN-YAN. SIN-YAN visits HO-KAN but she discovers that he is missing. She finally finds him and they reconcile with each other. SIU-KA's foster mothers discover that she has changed and they worry that KA-KEUNG has deserted her. After visiting the temple with FOON-HEI, SIU-KA brings him home for dinner. FOON-HEI discovers from SIU-KA's family photos that SIU-KA's birth mother was his old friend. FOON-HEI reveals to SIU-KA that he knew her birth mother and he tells her past stories to SIU-KA. CHEUK HOI and SIN-CHING attend a party at the cookery workshop together. They seize the chance to dance with each other and recall their romantic memory at the dance party.
S01:E21 - Line Walker
FOON-HEI always visits the foot spa for a rest. SIU-KA discovers that he suddenly leaves hurriedly after receiving a mysterious phone call. SIU-KA follows him and discovers that he has entered a 7-seater van. FOON-HEI is forced to speed up the land resumption project. Together with his subordinates, he urges the villagers to return the land but he hesitates after seeing the children there. SIU-KA and KA-KEUNG try to persuade the villagers by pretending to be hikers but their plan fail eventually. HOK-WAH, CHEUK HOI's supervisor and mentor, helps to make arrangements for CHEUK HOI's undercover officers to return to the police force. HO-KAN is overjoyed and he goes to the countryside with SIN-YAN. His sudden headache reminds him of the moment when he fell down from the building with SHIU-LEUNG. On the other hand, CHEUK HOI also discovers that SHIU-LEUNG's case is rather complicated and he decides to keep the undercover officers. When CHEUK HOI is carrying out investigation, his car is stopped by the police suddenly and the dead body of SHIU-LEUNG's relative is found in the boot of his car.
S01:E22 - Line Walker
After framing CHEUK HOI, the spy in the police force takes over his investigation unit. The spy discovers that the undercover officers' information is protected by password in the computer and he threatens CHEUK HOI to give him the password or he will harm MEI-YIN. CHEUK HOI is brought to the investigation unit but he escapes eventually. Everybody knows that CHEUK HOI is missing and people from the triad organization try to search for him by offering huge reward. After meeting with SIU-KA's foster mothers, FOON-HEI believes that SIU-KA is her daughter and SIU-KA discovers it accidentally. SIU-KA asks MUK-WING to help checking the identity of the 7-seater van owner who arrived at her foot spa earlier. She discovers that the owner is a woman called HEI-MEI. SIU-KA and KA-KEUNG sneak into HEI-MEI's office to carry out investigation but HEI-MEI's subordinates capture them. After a long period of investigation, HO-KAN and SIN-YAN finally find the murderer who killed SHIU-LEUNG and they capture him.
S01:E23 - Line Walker
SIU-KA and FOON-HEI are being attacked by their rivals on the street. CHEUK HOI sneaks into the police station to carry out investigation but the spy discovers him. The spy tries to kill CHEUK HOI but he falls into CHEUK HOI's trap accidentally and he loses his personal computer. CHEUK HOI tries to rescue SIN-CHING and they hide away in the ruins. CHEUK HOI worries that SIU-KA will be upset for nobody is carrying investigation on FOON-HEI's injury. He tries to investigate the case with KA-KEUNG and they finds the attacker successfully. After the incident, all gangsters know that KA-KEUNG has taken revenge for FOON-HEI and this enhances his status in the gang. The police is looking for SIN-CHING but they fail to find her. SIN-YAN is very worried. HO-KAN tries to calm her down by exchanging information with CHEUK HOI secretly. He helps SIN-YAN to talk to SIN-CHING on the phone and SIN-YAN is deeply touched.
S01:E24 - Line Walker
FOON-HEI wants to go travelling with SIU-KA and her foster mothers. SIU-KA discovers that FOON-HEI actually wants to run away. In order to carry out investigation on the land resumption project, KA-KEUNG requests to collaborate with HEI-MEI. SIN-CHING discloses her whereabouts carelessly and CHEUK HOI runs away with her. Luckily, SIN-YAN tries to help them by distracting the police. When FOON-HEI goes to the foot spa, an attacker suddenly arrives with a knife. With continuous efforts, SIN-CHING finally gets the criminal evidence from the spy's computer. CHEUK HOI brings the criminal evidence to the lecture hall where the spy is staying. SIN-CHING is worried and she seeks help from SIN-YAN and the other undercover officers. After learning the HEI-MEI insists to kill FOON-HEI so that she could complete the Northeast project, KA-KEUNG suggests to FOON-HEI that he could pretend to kill him and get his position so that HEI-MEI will trust him. This could help FOON-HEI to hide away from HEI-MEI as well. FOON-HEI agrees but their plan is not successful...
S01:E25 - Line Walker
FOON-HEI is captured by HEI-MEI's subordinates. HEI-MEI wants KA-KEUNG to show his loyalty by killing FOON-HEI with a gun. SIU-KA and her foster mothers arrive coincidentally. HEI-MEI asks her subordinates to chase after SIU-KA's foster mothers and kill them. MUK-WING learns about FOON-HEI's matter when SIU-KA is drunk. He is enraged and he decides to break up with KA-KEUNG. The spy is discovered and captured by the police. CHEUK HOI questions the spy but he commits suicide. KA-KEUNG tries to vent his anger at work and he completes the land resumption project at Northeast New Territories swiftly. After finishing his works, KA-KEUNG tries to look for SIU-KA but MUK-WING refuses to tell him the truth. KA-KEUNG attends the funeral and HEI-MEI suddenly arrives. HEI-MEI reveals that she has discovered KA-KEUNG's secret already. On the other hand, CHEUK HOI and his team members finally find the last undercover officer who worked for TO-HANG...
S01:E26 - Line Walker
SIN-YAN becomes CHEUK HOI's undercover officer to carry out investigation on "Mr SUNG", the one manipulating all the criminal activities behind the scene. According to information from HEI-MEI, "Mr SUNG" is formed by the merchant TSUI GA-BO, the councilor POU YEUNG SUK-WAN, the Director of Public Prosecution KWOK CHING and the tycoon PONG YIN-TING. SIN-YAN applies for a job at GA-BO's company to get close to him. SIU-KA joins SUK-WAN's electioneering team. KWOK CHING is SIN-CHING's supervisor and CHEUK HOI tells SIN-CHING about his matters. HEI-MEI helps KA-KEUNG to meet up with YIN-TING so that they could collaborate with each other. YIN-TING invites all members to discuss the Northeast development project and he plans to manipulate the stock market to gain money. SIU-KA offers sacrifices to her foster mothers at the worship hall. KA-KEUNG arrives and asks SIU-KA to forgive him. A group of attackers suddenly arrive to attack SIU-KA and KA-KEUNG rescues SIU-KA desperately.
S01:E27 - Line Walker
When SIU-KA leaves the hospital, she discovers that MUK-WING is injured. She persuades MUK-WING to leave the gang. SIN-YAN introduces GA-BO's mistress to HO-KAN. They play trick so that CHEUK HOI could capture GA-BO. However, the investigation on GA-BO is not smooth and KA-KEUNG decides to take revenge by himself. MUK-WING is short of money and he almost commits crime. SIU-KA helps him and suggests to CHEUK HOI that MUK-WING could be his informer for the investigation on YIN-TING. GA-BO is released for there is not enough evidence to charge him. However, he is kidnapped by a mysterious person right away. MUK-WING makes excuse to visit YIN-TING's home for investigation but he is not able to find any CCTV at his home. On the other hand, SIN-CHING finds an important evidence against KWOK CHING from some old documents. KWOK CHING discovers it and he asks somebody to kidnap SIN-CHING. He then threatens SIN-YAN with the life of SIN-CHING. CHEUK HOI discovers that SIN-CHING is in danger and he tries to carry out investigation to find the missing SIN-YAN.
S01:E28 - Line Walker
When the police try to capture KWOK CHING for investigation, he is suddenly missing. Since KWOK CHING is unmasked, SUK-WAN is losing support in the election and SIU-KA helps her by offering suggestions to resolve the problems. CHEUK HOI plans to arrest SUK-WAN on the election day but SUK-WAN is missing suddenly. CHEUK HOI visits KA-KEUNG and persuades him to change his mind. However, KA-KEUNG decides to take over YIN-TING's project and he plans to invest a large amount of money to fight for his own justice. HO-KAN suffers from serious headache regularly after the injury. On the other hand, SIU-KA suddenly arrives at the triad organization with an old person for she wants to compete with KA-KEUNG for the gang leader's position. MUK-WING sneaks into YIN-TING's office for information again and he is captured. KA-KEUNG learns that MUK-WING and SIU-KA are captured by YIN-TING. He visits YIN-TING with HEI-MEI in exchange for MUK-WING and SIU-KA's lives.
S01:E29 - Line Walker
All senior gang members suddenly arrive at HO-KAN's office to accuse KA-KEUNG and HO-KAN for cheating their money. HO-KAN doesn't want SIN-YAN to be hurt and he asks CHEUK HOI to help hiding him. KA-KEUNG returns home alone and he is shocked to discover YIN-TING and HEI-MEI's dead bodies. The police say that he is suspected of murdering and they capture him. Since KA-KEUNG is arrested by the police, SIU-KA becomes the gang leader successfully. SIU-KA is worried about KA-KEUNG and she tries to collect evidences to help him but she finds nothing useful. SIN-CHING investigates the videos of the case and she discovers some useful evidences to help KA-KEUNG. However, the evidences are replaced during the hearing. SIN-CHING believes that CHEUK HOI has done it and she is disappointed. SIN-CHING feels that she is not able to safeguard justice and she resigns from her prosecutor position.
S01:E30 - Line Walker
SIU-KA learns that KA-KEUNG's situation is getting bad. She tries hard to find supporting evidences for KA-KEUNG and she eventually helps him to overturn the court's decision. KA-KEUNG is released and he decides to launch the Northeast project right away. HO-KAN tries to stop him but he is suddenly ill and SIN-YAN arrives to save him. KA-KEUNG's project has failed and CHEUK HOI gets all the profits of the project. In fact, CHEUK HOI has been colluding with CHIN SHUI-ON. KA-KEUNG meets up with SIU-KA but SHUI-ON's killer arrives as well. SIN-YAN is depressed for HO-KAN is gone again but HO-KAN calls her to console her. HO-KAN has left Hong Kong for he wants to try a new medicine. CHEUK HOI always wants to join SHUI-ON's criminal group but SHUI-ON worries that his subordinates will betray him and he asks CHEUK HOI to get rid of TO-HANG's undercover officers.
S01:E31 - Line Walker
SIU-KA is threatened by CHEUK HOI and CHEUK HOI brings her to the basement where KA-KEUNG is staying. SHUI-ON is very pleased to learn that CHEUK HOI has killed SIU-KA and KA-KEUNG with a gun while all the people that KA-KEUNG was keeping in the basement were killed in an explosion. In order to get rid of other obstacles, CHEUK HOI kidnaps SIN-YAN to the beach to kill her with a gun but SIN-CHING she witnesses it for she has been following him. CHEUK HOI tells everybody that he has joined the criminal group successfully. He has captured SHUI-ON and his group members as well. However, SHUI-ON escapes eventually and he calls CHEUK HOI to inform him that he will disclose the information of all the undercover officers in Hong Kong. The gangsters try to kill KA-KEUNG and SIU-KA. During the critical moment, SIU-KA decides to commit suicide so that the gangsters will let KA-KEUNG go. CHEUK HOI receives a call from SHUI-ON and learns that SIU-KA and SIN-CHING are kidnapped by him. KA-KEUNG and CHEUK HOI decide to risk their lives to safe them...