Sworn spinster LEUNG SUM runs into TAI-KOON from a wealthy family while going grocery shopping, so she warns AUNTIE CHAI, who looks after TAI-KOON, to be wary of the recent surge in kidnappings. Unexpectedly, TAI-KOON is still abducted. After SHUM YAT-YIN, a brave and honest detective, arrests a thief on the street, he comes across his co-worker KAM WAH, who out of the blue starts defending the thief. KAM WAH sees someone holding a kid, and his furtive behaviour smells fishy to KAM WAH, who immediately runs after them. As their newly appointed supervisor from Britain pays much attention to the child abduction case, Detective Inspector LUI KWOK demands all the detectives to cancel their vacation and probe into the matter. Having taken bribes, KAM WAH distributes the money to the others, but YAT-YIN refuses to accept the money……

When KAM WAH goes to TAI-KOON's residence to collect the rest of the bounty after he successfully saves the child, he is spotted by AUNTIE CHAI, who immediately tells LEUNG SUM about it. Fishmonger MASTER PO comes to visit YING-YUET, so KAM WAH pretends to plan a banquet treat for YING-YUET, managing to deceive MASTER PO into treating YING-YUET to a banquet the next day. CHONG NGO-SHAN is the boss of the Shui Fung Nin Rice Store; whereas his concubine HO WAN-FONG is his right-hand woman. Suspecting that someone stole the rice, WAN-FONG comes up with an idea and easily makes the criminal give himself away. By coincidence, MAN-TO also plans a banquet treat for CHOI-TIP, so YUK-KIU tells YING-YUET to alter her schedule. That greatly exasperates MASTER PO, who even challenges MAN-TO to a competition to burn banknotes during the banquet……

YAT-YIN is reassigned to an idle position, and he comes across LEUNG SUM while looking for a lost dog named ROSE. LEUNG SUM mentions her background, so YAT-YIN suggests that she could post a notice in a newspaper to look for her family. LEUNG SUM's mentor, MEI-LAN, used to look after a girl called SOPHIE, who got married in Britain and recently follows her husband CHARLTON to return to Hong Kong because of her husband's job relocation. SOPHIE also pays LEUNG SUM $5 a day to cook for them. After leaving the newspaper office, LEUNG SUM and YAT-YIN bump into a mentally ill woman, MADAM LEUNG, during which YAT-YIN even helps her locate the whereabouts of her husband SZETO CHI-LEUNG. Therefore, they get to know the boss of a trading company, NG SAI-CHEONG. KAM WAH owes $500 in gambling debt, so he comes up with an idea……

With all the prostitutes of Foon Tak gathering in the lobby, YUK-KIU and CHOI-TIP respectively pressure YING-YUET to tell KAM WAH to return the money to them. SHEK KAU reads the family tracing notice posted by LEUNG SUM, so all of them start guessing which part on her body her birthmark occurs. YING-YUET happens to look for KAM WAH, who turns out to have sneaked into LEUNG SUM's home and peeked at her birthmark. Suddenly, YING-YUET and LEUNG SUM have a quarrel, during which YING-YUET blames LEUNG SUM again for having caused them to be kidnapped years ago. Having gone into debt by gambling at a casino, KAM WAH is under SAI-CHEONG's threats to work for him. All the prostitutes from the four big brothels assemble outside of the residence of the Commissioner on Banning of Prostitution, requesting to meet up with him, but SOPHIE refuses to let them in……

YAT-YIN manages to rescue CHI-LEUNG from SAI-CHEONG's henchmen all by himself and flees. Midway through, he runs into MADAM LEUNG and LEUNG SUM, so YAT-YIN guides them to take shelter in a safe place for the time being. Upon his return to the police station, YAT-YIN directly reports to his supervisor, a westerner, with regard to the situation of CHI-LEUNG and human trafficking, above which he even successfully convinces his supervisor to go to the safe house in person. However, when they arrive there, they find the house empty. With the prostitutes from the big four brothels once again gathering outside of the commissioner's residence, SOPHIE is unable to resist enormous pressure from the masses anymore, so she expresses that the commissioner, CHARLTON, agrees to give them a five-year buffer period. Through his investigation, YAT-YIN surprisingly uncovers that NGO-SHAN asked SAI-CHEONG to help look for his long lost biological son……

YING-YUET reveals her plan to YUK-KIU, which is to hold an event called "The last night" before the ban on prostitution takes effect so as to reap large profits from their clients, and in the meantime, some of them might even find opportunities to marry themselves off. During that night, though all of them are anxiously anticipating, to their surprise, only a handful of clients patronize there. Following their departure from the brothel, CHOI-TIP plans to rent a cheaper room together with CHEUNG-MEI and CHUN-CHU at the Ping On Inn; whereas YING-YUET claims that she has rented a room in a hotel. Out of the blue, MADAM LEUNG, who is temporarily staying in LEUNG SUM's place, attempts to commit suicide, so the others hope that she will be admitted in a mental hospital as soon as possible……

Apart from being demoted to uniform police officer, YAT-YIN is also dispatched to patrol the cemetery area on night shifts. LEUNG SUM goes to the Ping On Inn to visit YING-YUET, who instead warns LEUNG SUM to keep her nose out of her business. When YING-YUET goes to meet up with YUK-KIU, YUK-KIU introduces her to be an escort girl. After an Indian security guard is killed by a criminal during a bank heist murder case, YAT-YIN successfully solves the case, however, YIU-WAI implies that YAT-YIN is doomed to be a uniform police officer for the rest of his life. Summoning KAM WAH, SAI-CHEONG commands him to rescue the bank robber. Boss KEUNG arrives at the warehouse of the Shui Fung Nin Rice Store for purchasing negotiations, during which MAN-TO mistakes low quality rice for the high quality one and tries to sell him the low quality rice. After the incident, NGO-SHAN lays the responsibility of educating MAN-TO on WAN-FONG's shoulders……

After KAM WAH informs LEUNG SUM that YING-YUET is detained, LEUNG SUM manages to borrow $30 to bail her out. LEUNG SUM then takes YING-YUET back to her home, but the others refuse to accept YING-YUET, leaving LEUNG SUM no other choice but to leave her place together with YING-YUET. NGO-SHAN invites YAT-YIN back home to discuss his family affairs, and their conversation is eavesdropped on by MAN-TO. In order to help YING-YUET to start anew, LEUNG SUM volunteers to take a 50 per cent cut in her salary, hoping that SOPHIE will hire both of them at the same time. LEUNG SUM is informed that her biological father shows up, however KAM WAH discovers that the so-called father is in fact a swindler. With the bank robber, BIG GUY YING, being transferred to court for trial, SAI-CHEONG has someone free him in transit and arranges a getaway ship to send him away……

The story of KAM WAH bravely saving YAT-YIN receives significant media coverage. Meanwhile, YING-YUET frankly admits that she grows fond of KAM WAH while noticing that LEUNG SUM has a thing for YAT-YIN. To her surprise, LEUNG SUM obstinately denies that she has feelings for YAT-YIN. SOPHIE discovers that CHARLTON had a fling with a woman from Tong Sai before he met her, so CHARLTON frankly admits that he has an illegitimate daughter who is currently in Sai Wan. After CHARLTON acknowledged paternity of the illegitimate daughter, YING-YUET comes to realise that the daughter is actually CHOI-TIP. She can't take it anymore and eventually decides to resign. YEE-LING runs away from home, so MAN-TO, who tries to get himself a second wife, takes the initiative to propose marriage to YING-YUET. Seeing that he is willing to offer her very generous terms for the privilege, YING-YUET cannot help feeling tempted……

After being reassigned to work on day shifts, YAT-YIN goes together with UNCLE CHOI to the market to collect protection funds, but he fails the mission. MAN-TO and YING-YUET pretend to coincidentally bump into NGO-SHAN, who then invites them to dine with him, during which YING-YUET tries to curry favor with NGO-SHAN and eventually succeeds. As for KAM WAH, he appears to be very nervous after seeing YING-YUET meet the Chong family, which makes YING-YUET feel happy on the inside. Making things difficult for YAT-YIN, LUI KWOK specifically appoints KAM WAH to lead YAT-YIN to the market to collect bribes. Upon his return home, YAT-YIN, while feeling he has failed his father due to his corrupt behavior, keeps hitting his head against the wall as self-punishment. With LEUNG SUM experiencing an upset stomach which is getting worse, SOPHIE goes to probe into the matter and finds out that LEUNG SUM has fallen in love with YAT-YIN……

The public have been singing the praises of YAT-YIN ever since he successfully saved the commissioner's daughter, making YAT-YIN start agreeing to what KAM WAH said to him. To express her gratitude to YAT-YIN, CHOI-TIP not only gives him a luxury watch as a gift, but also invites him to the family party held by CHARLTON. Knowing that LEUNG SUM cannot be his dance partner, KAM WAH then invites YING-YUET to attend the party. At the party, LUI KWOK and the others all congratulate CHARLTON on his recent promotion to Chief Superintendent; whereas KAM WAH, seizing the opportunity when no one else is around CHARLTON, suggests that he should let YAT-YIN resume his former position. YIU-WAI receives a pot containing a mandarin orange tree together with cash worth thousands sent by SAI-CHEONG, who also invites LUI KWOK to meet him face-to-face. As expected, LUI KWOK arrives there, but the reason he came is to return the money to SAI-CHEONG……

Seeing that YING-YUET bursts into tears and leaves, LEUNG SUM goes to offer her some sympathy, instead she gets a very unpleasant earful from YING-YUET. While YING-YUET is walking alone in the heavy rain, she encounters NGO-SHAN, who immediately has someone deliver an umbrella. With a serialized fiction titled "Sai Wan Detective SHUM TSAT-KUNG Outwits Kidnappers" being published in sequential installments in the newspaper, the masses are aware that it's a story about YAT-YIN, and immediately it becomes the talk of the town. CHOI-TIP is enticed into reading the fiction, so CHARLTON, who knows perfectly well where the story of SHUM TSAT-KUNG is derived from, comes to realise that CHOI-TIP has a thing for YAT-YIN. Meanwhile, suspecting that LEUNG SUM has fallen in love with YAT-YIN, SOPHIE starts teaching LEUNG SUM to check YAT-YIN's intention……

From the fiction, BROWN learns about the fact that YAT-YIN has been reassigned to an idle position so he inquires LUI KWOK about the issue, leaving LUI KWOK no other choice but to reassign the job duties. Though KAM WAH actively tries to defect to YIU-WAI, YIU-WAI refuses to take him in because he is of the opinion that KAM WAH is a double agent. Being discharged from the hospital, MAN-TO returns home only to find that YING-YUET and NGO-SHAN are waiting for him. While there, NGO-SHAN announces that he is going to marry YING-YUET. After the wedding banquet, KAM WAH and LEUNG SUM bump into an orphan, NG CHIN, who was abandoned by his parents, and LEUNG SUM manages to convince him to stay in an orphanage. CHARLTON teaches CHOI-TIP to check YAT-YIN's intention, which on the contrary makes YAT-YIN awaken to the fact that LEUNG SUM also tried to ferret out his intention……

With the orphanage filing a police report after finding out that six children have gone missing, KAM WAH cannot help but think something smells fishy there. For the first time ever, LEUNG SUM goes to cook for YAT-YIN, which is discovered by KAM WAH, so LEUNG SUM urges KAM WAH not to let her mentor know about that. Having learned that LEUNG SUM starts seeing YAT-YIN, SOPHIE volunteers to help LEUNG SUM, trying to get MEI-LAN's approval of the relationship. Unfortunately, MEI-LAN is strongly opposed to letting LEUNG SUM date anyone. After knowing that YING-YUET is pregnant, NGO-SHAN is overwhelmed with joy, above which he even warns WAN-FONG and MAN-TO to keep their hands off YING-YUET. YAT-YIN receives a tip-off that the six children were seen begging on the streets in Shaoguan, following which the police classify the case as juveniles that ran away……

Having enquired AUNTIE LAI for LEUNG SUM's whereabouts, KAM WAH and YAT-YIN go to her rescue, and thereby LEUNG SUM has to stay the night together with KAM WAH and YAT-YIN. At night, LEUNG SUM confides in YAT-YIN through the wall in the next room; whereas KAM WAH out of the blue sees MEI-LAN trying to hang herself while he walks away from the house. YAT-YIN unmasks the witness who claimed to see the six children in Shaoguan as a complete charlatan, and comes to realise that YIU-WAI is behind the whole thing. One night after an intense downpour, the rain washes away the dirt that they covered the six children with and the body remains are exposed. Though KAM WAH finds YIU-WAI and intends to arrest him, he is instead severely beaten up by YIU-WAI's henchmen……

Inside the Walled City, YAT-YIN comes under heavy fire, and in a split second, KAM WAH goes to his rescue, managing to bring him back from the brink of death. Joining forces together, the two successfully dismantle the network of the kidnapping ring, therefore they are dubbed as the "Two Brave Cops". Pained and grief-stricken, LUI KWOK's mother blames LUI KWOK for the death of her grandson, so LUI KWOK is determined to take revenge against YAT-YIN. Meanwhile, the other cops in the No. 7 Police Station are all positively influenced and motivated by YAT-YIN and KAM WAH, showing great enthusiasm at work. According to BROWN, all of the superintendents are very satisfied with YAT-YIN's performance, and it's most likely that YAT-YIN is going to be promoted to Detective Inspector. LUI KWOK receives an anonymous phone call, threatening to kill his wife and mother if he refuses to meet him……

YING-YUET begs LEUNG SUM not to expose NGO-SHAN's criminal activities, otherwise she and her unborn baby will lose the breadwinner of their family. At the funeral held for LUI KWOK's mother, YAT-YIN and the others come to pay tribute to the deceased however, LUI KWOK not only tells them to leave, but also blames YAT-YIN for his mother's death. Later on, YAT-YIN goes to pay tribute to his late father, only to find out that his tomb was severely damaged. Suddenly, LUI KWOK appears and frankly admits that he is the one who did this, on top of which he even arrogantly brags that all big four Detective Inspectors will definitely pick on him in the future. While LEUNG SUM is decorating the wedding room alone, YAT-YIN returns and tells her that he would like to push back their wedding date because he plans to marry CHOI-TIP first, promising that he will come back to her after a year. Devastated, LEUNG SUM dissolves into tears……

At the wedding ceremony, CHARLTON suddenly has a heart attack and passes out, which terrifies everyone at the scene. In view of this, NGO-SHAN orders the gunman to abort the assassination of YAT-YIN. LEUNG SUM suffers severe injuries as a result of the attack, lapsing into a coma. After regaining her consciousness, she blurts out towards KAM WAH that she knows who is the culprit. She then discusses with KAM WAH and concludes that NGO-SHAN might harm YING-YUET. In order to help YING-YUET run away, KAM WAH deliberately denounces NGO-SHAN's crimes one by one, which is overheard by WAN-FONG, who happens to pass by the front entrance. Though YAT-YIN is despised by the people in the neighbourhood after the serialized fiction depicts YAT-YIN as a two-timer, KAM WAH still hands him the address showing where LEUNG SUM is hiding, urging him to bring along some food and pay a visit to LEUNG SUM……

Following the shooting of CHARLTON, the gun found at the crime scene is later confirmed to be YAT-YIN's firearm, so BROWN immediately orders the arrest of YAT-YIN who is still at large. Finding himself nowhere to hide, YAT-YIN has no other choice but to flee to the shed that LEUNG SUM and YING-YUET are hiding in, leading to a reunion of all four of them. Based on KAM WAH's analysis, three of them should flee simultaneously in three directions; whereas KAM WAH himself stays behind, seeking opportunity to clear YAT-YIN's name. LEUNG SUM, who was going to rush to the pier, notices that YING-YUET shows the signs of miscarriage while running away with her, leaving them no other choice but to go back to the Spinster House and take shelter there for the time being. Just as SOPHIE and CHOI-TIP are getting ready to return to Britain, YAT-YIN makes a sudden appearance, vowing that he will personally seek revenge for CHARLTON's death……

YAT-YIN and KAM WAH are nowhere to be found after they fell off the cliff; whereas NGO-SHAN has been riding high ever since and eventually claims supremacy over the others. Though AUNTIE CHAI advises LEUNG SUM to go back to Mainland China, LEUNG SUM decides to stay for the sake of YING-YUET. YING-YUET gives birth to a baby boy, on the heels of which NGO-SHAN not only warns everyone to keep YING-YUET away from the infant, but also severs his ties with YING-YUET. Out of the blue, NGO-SHAN's son vanishes into thin air. On the other hand, it's reported by the serialized fiction in the newspaper that the "Two Brave Cops" have reemerged. A journalist passes a note in secret after meeting LEUNG SUM and YING-YUET, so the two follow the address and arrive at a shed, where they find an infant. While meeting up with NGO-SHAN, LUI KWOK is ambushed and is tricked to confess all his criminal activities……