LAW YIU-WAH teaches Chinese Language in a band 3 school called Qiqihar Association Lam Tin Kwong Memorial Secondary School. He believes that “human nature is evil” and therefore a teacher should control the student strictly while teaching them but the students do not appreciate his approach at all. Influenced by his grandfather LAW CHUN-BONG, YIU-WAH decided to be a policeman since childhood but his mother opposes the idea strongly for YIU-WAH’s soldier father was killed while carrying out his duty. YIU-WAH is a filial son and he gives up his aspiration eventually. The school bowling team of Lam Tin Kwong used to be very famous in Hong Kong but the team is no longer active. The school team is going to have a friendly match with their enemies from But Kau Yan School……

YIU-WAH decides to apply for a police job and CHUN-BONG gives him tactical training but YIU-WAH still fails to get the job. However, he later receives a phone call from an employment agency and realizes that the Senior Superintendent of Intelligence Bureau of the Police Force, POON KWOK-SHING, wants him to be an undercover teacher in Lam Tin Kwong Memorial Secondary School for investigation of a campus drug case. YIU-WAH doesn’t really like to return to the school but he accepts the offer eventually for he really wants to be a real policeman. In order to collect information from the students, YIU-WAH changes his teaching style completely and he tries to get close to K4 in every ways but K4 simply ignores him. HO MIU-SUET, an enthusiastic new teacher, comes to teach Physical Education and General Studies in the school……

Encouraged by MIU-SUET, TIN-YAN finally reveals that he brings “weapon” to school for self-protection only because K4 always bully him. MIU-SUET wants to help TIN-YAN but K4 have asked their parents to make complaint to the PTA and they even report the case to the police. The Police Superintendent eventually exercises discretion to issue a caution to TIN-YAN. MIU-SUET and YIU-WAH work together to help TIN-YAN and K4 finally stop fighting against TIN-YAN. Meanwhile, YIU-WAH suspects that KA-PO has been manipulated by the triad organization to offer Enko dating service and he starts chatting with her on the internet with a fake identity. His nosy cousin YIU-CHO accidentally discovers KA-PO’s contact and he dates her stealthily. This causes great trouble to YIU-WAH…

YIU-WAH is proved to be innocent and KA-PO is not connected with any triad organization. YIU-WAH doesn’t need to continue his investigation on KA-PO but he needs to counsel her instead. YIU-WAH and MIU-SUET invite KA-PO’s mother for a meeting. They realized that KA-PO is not having any financial difficulties and she practices Enko dating just to satisfy her material need. KA-PO wants to withdraw from her studies. MIU-SUET doesn’t want to give her up and she persuades her to return persistently. KA-PO eventually agrees to return. The new transfer student TSEUNG TSUN has conflict with K4 on his first day of school. CHAK-KEI and FAN TAI try to give him a hard time by beating him. NG KA-YEE informs YIU-WAH about the case secretly. TSEUNG TSUN invites K4 to a fight and YIU-WAH follows them. YIU-WAH is shocked to find that TSEUNG TSUN has brought a group of gangsters from the triad organization…

TSEUNG TSUN’s father TSEUNG HUNG is the former head of a triad organization. He comes to the school and the principal receives him anxiously. All staffs in the school worry that their students will be influenced by the triad organization but YIU-WAH seizes the chance to approach TSEUNG TSUN for collecting information. On the other hand, MIU-SUET discovers that all students are isolating TSEUNG TSUN so she invites him to the school basketball team, hoping that this would help him to develop a better relationship with other students. CHAK-KEI is upset that TSEUNG TSUN has stolen his credits in the team so he fights with him. Both of them are punished afterwards. While having a detention, TSEUNG TSUN receives a phone call from a friend asking for help and he rushes to the place immediately. He is in danger and TSEUNG HUNG arrives on time to save him……