After being rejected from a police college, Qin Feng (Liu Haoran) goes to Bangkok for a vacation. He plans to spend time with his “uncle” Tang Ren (Wang Baoqiang) who is reputed to be the number one detective of Chinatown in Bangkok. Tang Ren turns out to be a sleazy petty swindler who happens to be an underling of local incompetent police sergeant Kon Tai (Xiao Yang). Meanwhile, the main suspect in a local gold robbery case, Sompat, is murdered and the gold goes missing. The gold belongs to prominent local gangster Mr. Yan (Chin Shih-chieh); as a result, the case gains a prominent status in the local police department. Kon Tai and his rival in the department, the ambitious Huang Landeng (Chen He), are put into competition by the police chief to solve the case and retrieve the gold in order to be appointed the next deputy chief.
After a series of mischievous adventures with Qin in Bangkok, Tang is pursued by police as he is the main suspect in Sompat’s murder, being the last person to enter and leave Sompat’s workshop where he was murdered. Tang seeks the help of Qin, who turns out to be a prodigy in solving crimes from the knowledge Qin garnered as a mystery novel lover. During their exodus from the pursuit, Qin and Tang are captured by Sompat’s cohorts who wish to locate the now lost gold. Qin and Tang, now wanted criminals, are eventually able to escape and hide in the home of Xiang, Tang’s landlady and the #1 beauty in Chinatown. However, they are followed by the gold robbers, who arrive just before Kon’s meeting with Xiang in the same home, leading to an awkward confrontation between all parties.
Qin later finds out why Tang is implicated: on the day of the murder, Tang received a call asking him to deliver a boxed Buddha statue from Sompat’s workshop at midnight. The pair, after deciding to stay in Thailand and risk their lives, goes to the parking lot where Tang delivered the box. Qin finds a trace of fish in the area, after which they go to a nearby seafood market and a junk yard. That night, Qin and Tang searches the workshop, narrowly avoiding an encounter with the robbers. Qin deduces that Huang Landeng’s assistant, Tony, is part of the scheme.
To solve the murder, Qin and Tang must watch the surveillance footage of the workshop. As it is kept in Huang’s computer, Tang lures the police force away while Qin and Kon retrieve the footage and other documents about Sompat. After translating the documents, Qin finds that Sompat’s son went missing a year prior and that Sompat frequented a café. Following the trail, Qin and Tang are led to Snow (Zhang Zifeng), who was a school classmate of Sompat’s son.
Qin and Tang are soon captured and led to Mr. Yan, who gives them 3 days to find the stolen gold. Qin and Tang split up, Qin meeting Snow for a second time and Tang being pursued again by Huang. Qin discovers that Snow’s stepfather, who he meets, works at the junk yard near the parking lot, making him a suspect.
Qin and Tang rejoin at the workshop, where they hypothesize that the murderer hid in the workshop for one week, killed Sompat before Tang’s delivery, and escaped the workshop by hiding in the box Tang delivered. They are suddenly ambushed by the masked murderer, who sets the workshop on fire. Qin and Tang narrowly escape.
After learning that Xiang is kidnapped by Tony, Qin and Tang confront and defeat him. The pair delivers Xiang to the hospital, where they witness a shootout between the police and the other three robbers. Qin and Tang returns to Snow’s home yet again, but finds her on the verge of death, supposedly drugged by her stepfather. After delivering Snow to the hospital, Qin finds the true story behind the murder in Snow’s journal. Snow was raped by Sompat, which her father found out, leading him to kill Sompat. The gold robbery and the murder are unrelated.
Qin and Tang finally reveal to the police that the lost gold was hidden in a statue at the workshop, after a lengthy car chase around Bangkok. At the hospital where Snow resides, Qin and Tang convey their findings to the police in the presence of Snow and her stepfather. After being exposed, the stepfather is accidentally killed by Kon’s car while he jumps out of a hospital window. Kon is subsequently promoted to deputy chief due to his prevention of the murderer’s escape, to the annoyance of a severely injured Huang.
However, Qin soon realizes that Sompat was homosexual, meaning he could not have raped Snow. He realizes that Snow was stalked by Sompat because he suspected her of killing his missing son. Thus, Snow planned Sompat’s murder, framed him for rape in her journal, and fabricated the evidence to get rid of both Sompat and her pervert father, who she loathed. Qin confronts Snow, but decides to leave her.
Wang Baoqiang as Tang Ren
Liu Haoranas Qin Feng
Tong Liyaas Xiang
Chen He as Huang Landeng
Xiao Yang as Kon Tai
Xiaoshenyang as Bei Ge
Pan Yueming as Lee
Marc Ma as Tony
Zhang Zifeng as Snow
Zhao Yingjun as Vietnamese