《七号差馆》这部剧讲述的是警察的故事，围绕着各种案件。 乐天女工不知就里的替人顶罪，导致一命呜呼，等待着自己沉冤得雪的一天。黄英姑与女儿一家自给自足盛行乐观，与邻居交情极好，而其子更是将黄英姑当成自己再生母亲一般看待。当下的香港，贪污盛行在贪党工作的黄英姑，因为欠债偶尔会替别人当做替死鬼偿还债务，做数日的牢房，在某次黄英姑不明就里之下代替，答应成为替死鬼却被人当成杀人犯判以死刑，黄英姑在行刑之前剪下自己的辫子，将自己的辫子交给华当做纪念，而黄英姑在死后，冤魂附身在辫子身上，因为辫子落在证物的房间无法出来，导致一困就是数10年

转眼，剑成长当上了警察，而十分正直的剑，因为不愿意贪污，只能看守政务房，在政务房时找到了莺的辫子，两个人相认。当年嫁祸黄英珠的叶家升成为了探长，将关公像移位黄英姑的冤魂，重获自由，十分思念华。剑帮助黄英姑寻找着华的下落，剑也在黄英姑的帮助之下，屡次破案命运使然，黄英姑找到了华，却发现华如同自己一样成为了替死鬼。

"Position No. 7" This drama tells the story of the police and revolves around various cases. The Lotte female worker scapegoats without knowing it, resulting in her death, waiting for the day when she will be avenged. Huang Yinggu and her daughter's family are self-sufficient and optimistic, and they have a good friendship with their neighbors, and their son treats Huang Yinggu as his own reborn mother. Corruption is prevalent in Hong Kong at the moment. Huang Yinggu, who works for the corrupt party, occasionally repays debts for others as a scapegoat because of debts. The prisoner was sentenced to death. Before the execution, Huang Yinggu cut off her braids and gave her braids to Hua as a souvenir. After Huang Yinggu's death, the soul of Huang Ying possessed the braids. A sleepy counts to 10 years

In a blink of an eye, Jian grew up and became a policeman, and Jian, who is very upright, can only guard the government office because he does not want to be corrupt. In the government office, Ying's braid was found, and the two recognized each other. Ye Jiasheng, who blamed Huang Yingzhu back then, became a detective, and moved Guan Gong's portrait to Huang Yinggu's wronged soul, regained his freedom, and missed Hua very much. Jian helps Huang Yinggu find Hua's whereabouts, and with Huang Yinggu's help, Jian solves cases many times. As a result of fate, Huang Yinggu finds Hua, but finds that Hua has become a scapegoat just like herself.