The officer in charge of Team A, CHIN HON-TO, leads the rookies of the Special Duties Unit (SDU)/Flying Tigers together with his current team members to conduct some outdoor training. While there, one team member, YU HOK-LAI, demonstrates how to successfully hop on the roof of the high speeding car driven by his co-worker, CHONG CHEUK-YUEN, from another roof of a moving car by solely depending on his own feeling and trust built between his team members. Having seen this, HOK-LAI's girlfriend, SO MAN-KEUNG, who is also one of the rookies, feels very satisfied. Unfortunately, MAN-KEUNG sprains her ankle while jumping...... Under orders to set out for an operation, HON-TO learns that ON TIN-MING and his three armed henchmen have taken a large amount of civilians hostage at the high court……

International drug dealer TSUI KEI-HAP is taken into custody by INTERPOL agents then back to his country to face trial, but he has to be accompanied by his personal doctor HON YU the whole journey because he suffers an acute disease. Out of the blue, they are ambushed and attacked by killers when on board the plane, and KEI-HAP is injured and sent to a Hong Kong hospital. During his hospitalization, the Hong Kong police force, under the request of INTERPOL, dispatch the SDU led by CHIN HON-TO to protect and escort the two to leave Hong Kong safely...... CHUNG WAI-YAN would like to resume her former duty as a CIB officer, so she is required to undergo several psychological evaluations. Although her superiors such as ZI-LUNG and the others are very satisfied with her performance, she is still under probation……

Mute NGAR, crippled FAI, blind MANDY and deaf LUNG are sworn sisters, and they run a business to sell sporting goods. However, the business is a mere facade, and in fact, they rob the rich and give to the poor once they find out that person makes ill-gotten gains. HON-TO trains WAI-YAN, trying to help her overcome her traumatic experience, but to no avail. Noticing that everyone is talking about the vacant position of the Chief Inspector, HON-TO learns from the Commissioner that CHI-LUNG has been appointed as the new Chief Inspector. With all the SDU members being invited to attend the PHAB’s Happy Day (Physically Handicapped and Able-Bodied), HON-TO re-encounters his first love NGAR in fencing competition, to his surprise, NGAR has become mute. CHEUK-YUEN and TAK-WAI help all the contestants complete their shooting training, during which TAK-WAI finds FAI irresistible and falls in love with her at first sight……

WAI-YAN sneaks into a gathering activity of a Japanese secret society after receiving intelligence in connection with its alleged involvement in a local poisoning terror. The most-watched Japanese show is about to relocate to film in Hong Kong, above which the Japanese superstar MIRYO FUJII is also going to take part in the show by then. Due to this, CHI-LUNG is under orders to dispatch HOK-LAI, MAN-KEUNG, CHEUK-YUEN and KA-MING to participate in the show as well. Off-duty CHEUK-YUEN happens to be there when a robbery takes place, during which he is astonished to see that his girl friend WAI-WAI has become a patrol officer. With the Japanese show "Running Army" officially starting filming, HON-TO and CIB staff are responsible for monitoring. Seeing that the carefree siblings from the SHU family come to take part in the show, HOK-LAI cannot help feeling surprised……

Former SDU sniper TIGER HO likes gathering information in his off time so as to help the police solve crimes in secret. HON-TO and CHI-LUNG announce that all the rookies have officially become SDU members, following which they celebrate with them. At midnight, HOK-LAI receives a text message from CHI-LAI, who makes some excuses to keep HOK-LAI there after he arrives at the shopping mall. When CHEUK-YUEN and TIGER HO have a target competition, TIGER HO is attacked and he deduces that must have something to do with his good friend, TIN SUN-HEI. Bumping into HON-TO and WAI-YAN on a street corner, CHUNG-CHAI is very delighted to see them, above which he even tells WAI-YAN about the story of HON-TO and CHEUK-YUEN's elder sister CHEUK-WAH. TIGER HO takes action to solve a drug trafficking case without knowing that SUN-HEI secretly sends someone to steal the drugs……

CHEUK-YUEN and his fellow SDU members go to round up TIN SUN-HEI, who, out of the blue, gets shot when raising his hands in surrender to their request. After CHI-LUNG receives the complaint filed by SUN-HEI, HON-TO is under orders to probe into the matter. Off-duty MAN-KEUNG and HOK-LAI run into CHI-LAI while out on a date, and CHI-LAI even shows them the photo she took together with HOK-LAI during HOK-LAI's visit to her exhibition. Testifying for SUN-HEI's case, all of the SDU members unanimously claim that they have no idea who shot SUN-HEI after SUN-HEI surrendered. HOK-LAI and the others go to HON-TO's home to have a hot-pot meal together, and they see SUN-HEI's interview, in which SUN-HEI alleges that the SDU members took the law into their own hands. After receiving intelligence, the CIB requests to dispatch the SDU to assist their mission……

YEE kills one of his enemies on the heels of his release from prison, and then returns to the garage that he and the other three jointly invested in to have dinner together. While there, he together with HAU, CHUNG and YAN reflect on the bygones, ranging from being sent to prison to the considerable hardship they all experienced in Vietnam years ago. CHI-LUNG transfers HOK-LAI, KA-MING and TAK-WAI to team B, making HOK-LAI their leader for the time being. After leaving the SDU, CHEUK-YUEN is transferred to the CIB, not only becoming WAI-YAN's co-worker but also reuniting with his former fellow member of the SDU, KAI-KWONG. When instructing WAI-WAI how to fire the gun, CHEUK-YUEN comes to realize that he is absolutely terrified of guns now. CHI-LAI and HOK-LAI's car breaks down, so they seek aid from the garage run by YEE and the others, without knowing that it triggers YEE and the others' motive to kill them……

HOK-LAI's former classmate NG CHO-HING runs a resources company, which becomes a listed company on the stock exchange. However, the company is under the terrorists' coercion for money laundering, and the financing of terrorist activities. After leaving the SDU, LIK-CHUEN opens a café called "Tiger’s café". HON-TO brings a congratulatory gift for him, and then makes an excuse to leave, hardly seeing HOK-LAI and the others. Accompanying MAN-KEUNG to attend the banquet hold by CHO-HING, HOK-LAI re-encounters CHI-LAI and her family members. Following the announcement made by CHO-HING that CHI-MING, a wealthy Malaysian, has invested in his company, CHUNG-CHAI intends to re-mortgage his current residence to get some money so as to invest in the stock market as well. CHO-HING makes a briefing to the boss of the money laundering syndicate, FURY CHICK, about the company business……

With FURY CHICK sending his henchmen to go on a rampage, the one in the cap standing aside to watch the whole scene turns out to be...... CHEUK-YUEN makes a report to his superior, revealing that WAI-YAN became addicted to drugs. WAI-YAN is then ordered to surrender her firearm and take a leave effective immediately. WAI-YAN is shot by a sniper, fortunately, HON-TO goes to her rescue in the nick of time. CHI-LUNG intends to send HOK-LAI and his fellow team members for training overseas. Worrying about MAN-KEUNG, HOK-LAI decides to tell HON-TO about her previous miscarriage tragedy, in hopes that he can help comfort MAN-KEUNG. CHEUK-YUEN asks WAI-WAI out for a date, during which he proposes marriage to her and succeeds. HON-TO gets ambushed by a man in a mask, who threatens to kill CHUNG-CHAI, so HON-TO lets himself get caught without making any resistance……

HON-TO leads the CIA Agent, KIM SAU-KEI, to inspect the headquarters of the SDU, during which they talk about several mysterious cases that happened over the past years. Among them, KIM SAU-KEI seems to be exceptionally interested in the case involving ON TIN-MING. After CHEUK-YUEN expresses that he would like to return to the SDU, HON-TO arranges for him to undergo an assessment. CHEUK-YUEN goes to the hospital to accompany WAI-WAI. Reflecting on the past, he cannot help feeling his sadness that is brimming over. For the sake of his family members' safety, CHI-LUNG pushes WAI-YAN into cooperating with him to find FURY CHICK. When HON-TO and his fellow team members raid the unit where illegal weapons are stored, WAI-YAN informs CHI-LUNG on the whereabouts of FURY CHICK. Surprisingly, WAI-YAN learns that KIM SAU-KEI and ON TIN-MING were actually childhood friends……