Berlatar pada tahun ke-14 masa pemerintahan Kaisar Chenghua, Tang Fan, seorang pejabat tingkat enam dan Sui Zhou, seorang penjaga seragam bersulam, bergandengan tangan untuk menghancurkan konspirasi untuk menjaga perdamaian dan ketertiban bagi rakyat.
Setelah bekerja sama untuk menyelesaikan kasus yang melibatkan putra Marquis, Tang Fan (Darren Chen) dan Sui Zhou (Fu Meng-po) mendapatkan ketenaran yang meluas dan membentuk persahabatan yang langgeng satu sama lain. Meskipun reputasinya mendahuluinya, Tang Fan tetap jujur dan jujur dalam tugasnya sebagai pelayan publik dan terus menyewa rumah yang sederhana. Tuan tanahnya ditemukan tewas di tempat tinggalnya mungkin karena bunuh diri, tetapi petunjuk mengarah pada kecurigaan dari permainan curang.
Setelah kasus ini diselesaikan, Tang Fan pergi ke Henan untuk menyelidiki hilangnya orang-orang di dekat lokasi makam mendiang Kaisar Song Utara. Ketika pelakunya terungkap, tampaknya dia hanyalah pion dalam konspirasi yang lebih megah. Ketika kasus-kasus besar terus menjangkiti ibukota dan kantor-kantor lokal, Tang Fan dan Sui Zhou bekerja keras untuk membuka kedok dalang yang sedang menarik dawai.
# Main Cast
Guan Hong as Tang Fan (Tang Runqing), A sixth grade prefecture judge of Shun Tian Magistrate Manor. He is optimistic, kind and known for being a glutton.
Fu Meng Bo as Sui Zhou (Sui Guangchuan), A sixth-grade imperial secret police (jinyiwei). He is a good cook and a skilled fighter.
Liu Yao Yuan as Wang Zhi, Duke of Xi Chang. Confidante of Wan Zhen'er. He is known for being both merciless yet upright.
# Royal family
Cai Heng as Zhu Jianshen, the Emperor
Alyssa Chia as Wan Zhen'er (Imperial Noble Consort Wan), the Emperor's favorite consort
Fang Xiao Li as Empress Dowager Zhou
Liu Shi Jie as Zhu Youtang, the crown prince
Yang Kai Ru as Virtuous Consort Ji, mother of the Crown prince. Was poisoned to death by Wan Zhen'er.
Zhao Xiao Lu as Princess Gu An, cousin of the current Emperor and daughter of Emperor Jingtai. She harbors hatred toward the current ruler for the plight of her family.
Yang Kai Cheng as Wang Xian, prince consort. Despite being autistic, he is highly talented in weapon making and invented Bo Lang, a bomb that caused massive explosion.
Li Tai Yan as Emperor Jingtai
# People around Tang Fan
Huangyang Tian Tian as Dong'er, a maidservant who delivers food to Tang Fan and later follows him. She is highly intelligent and analytical despite her young age. She likes Sui Zhou.
Mao Yi as Pei Huai, a skilled physician. Tang Fan's close friend. He likes Tang Yu.
He Nan as Duo Erla, an Oirat girl who clashes with Tang Fan and later befriends him. She came to the Capital in search of her long-lost lover.
Pan Shi Qi as Tang Yu, Tang Fan's sister. She was married to an abusive husband, but got a divorce and later get together with Pei Huai.
Lu Jin Hao as He Cheng, Tang Yu's son and Tang Fan's nephew
La Mu Yang Zi as Dong Gu, owner and chef of Dong Ji restaurant
Zhang Yi Long as Wu Yun Bulage (Wu Yun), Duo Erla's follower. He is knowledgeable about weaponry and horses.
# People around Sui Zhou
Xiong Xiong as Xue Ling, Sui Zhou's subordinate. An imperial secret police.
# People around Wang Zhi
Yu Ming Xuan as Ding Rong, Wang Zhi's subordinate
Steve Yoo as Jia Kui, a former Baihu soldier who was captured by Sui Zhou and works for Wang Zhi
Wei Yun Xi as Mother Cui, manager of Huanyi Brothel
Wang Mao Lei as Li Zilong
Leader of Bai Yue Sect. Descendant of the royal family of the previous dynasty. He aims to stage a coup.
Liu Bin as Shang Ming, Duke of Dong Chang
Chen Wei Xu as Wan Tong, head of Jinyiwei guards. Wan Zhen'er's brother.
Gao Lan Cun as Wan An, Chief Grand Secretary. Ally of Li Zilong.
Cao Yang as Pan Bin, prefecture judge of Shun Tian Magistrate Manor. Tang Fan's senior.
Qu Ge as Lao Sun, coroner at Shun Tian Magistrate Manor
Qian Ru Fu as Lu Zhi, magistrate of Tong Zhou (later Yun He)
Chen Meng Yao as Feng Qingzi, a courtesan at Huanyi Brothel
Gong Zi Qi as Lin Chaodong, Feng Qingzi's lover
Zhang Zhong Xing (张仲兴) as Zheng Ying, Duke of Hou An
Luo Mao Yang (罗茂阳) as Zheng Cheng, elder son of the Hou An Manor. A wanton playboy. He was killed by Zheng Ying.
Zhou Hang as Zheng Zhi, second son of the Hou An Manor. He killed Zheng Cheng, as he felt that he is an embarrassment to the family name.
Yang Chang Qing as Liu Xiang, head eunuch. He killed Han Zao in an attempt to frame Royal Consort Wan.
Shi Di Wen as Han Zao, the crown prince's study companion
Shang Cheng Jun (尚城君) as Huang Jinglong, magistrate of Ji An City. He is known for his cruel and harsh punishments, resulting in the death of many prisoners.
Yu Yang as Huang Ying, Huang Jinglong's subordinate
Liu Yao Yuan as Yang Fu, a criminal captured by Huang Jinglong that looks identical to Wang Zhi.
Lu Zhan Xiang as Nie Ping, a boy that was jailed for stealing money to buy medicine for his mother
Gao Jian as Chen Xu, a general guarding the borders. Known for his uprightness and fierce loyalty to the country
Dong Li Wu You as Xiao Niqiu, leader of the beggar children. Helps Wang Zhi in gathering intelligence.
Tang Zi Yue as Xiao Chizi, one of the beggar children. Helps Wang Zhi in gathering intelligence.
Yu Yuan as Yu Zhengpeng, elder son of Yu family. A general. He hated Wang Zhi as he believed he caused the death of his father.
Lin Xu as Yu Zhenglin, second son of Yu family. A minister. He tried to turn the citizens against Wang Zhi as he thought he killed his family
Yuan Qiao as Yu Xiulian, daughter of Yu family. She admires Sui Zhou, whom she was almost betrothed to.
Chu Tian Shu (楚天舒) as Zhang Degui (Chef Zhang), chef of Yu family. He has a secret crush on Yu Xiulian and after failing to have his feelings reciprocated, killed the entire Zhang family.
Zhao Yang as Zhu Jianmou, a prince who often helps out the needy and is known as "Great Kind Person". However, he is actually a serial murderer who kills foreign young girls and dig out their heart, due to having being betrayed by his lover.
Shi Da Mao as Qian Tai, a tea merchant who trafficks children
Lu Lin as He Lin, Tang Yu's abusive husband
Li Li Qun as Ma Lin, the wealthiest merchant of Yun He who is is in charge of the silver mines. Subordinate of Li Zilong.
Yang Huan as Li Mao, a scholar who is concerned about the welfare of mine workers
Yang Tun as Ma Yuancong, Ma Lin's son
Ge Xing Jia as Ma Rufu, housekeeper of Ma manor
Zhang Yue (张岳) as Er Tao, leader of the mine workers
He Zi Ming as Li Fei, a former soldier. He impersonated Sui Zhou, using his name to rob the officials and distribute the money to the poor.
Yan Wei Liang as Li You, Li Fei's subordinate
Zhang Bai Jia as Qing Ge, a famous courtesan. Li Zilong's god-daughter, who is planted as a mole in Huanyi Brothel.
Hu Xiao (胡潇) as Sun Da, an official guarding the ice house
Li Yuan Yuan (李元元) as Jin Sanniang, seller of ice in the black market. Descendant of a family who helped build the palace's secret tunnels.
Shu Ya Xin as Alasi / Ding Man, an Oirat spy sent to the palace as an eunuch. Duo Erla's lover.
Jiang Feng as Gao Yi, an accomplished general who was captured by the Oirats while protecting the former Emperor
Jia Shu Yi as Madame Gao, Gao Yi's wife