Wang Yu, a private detective hired to investigate a routine case of marital infidelity, ends up becoming the target of a drug trafficking operation led by a powerful Japanese businessman.
Learning of childhood friend Meihua's death, Lingling goes to Japan to find Meihua's sister, Meifeng. Brutal gangsters demand Lingling return an item Meihua stole, and hold Meifeng hostage. Old friends help Lingling confront the gang.
Chow Si-Pak, Dried Pork, Lo Ka-Ying and Yo are cousins who are unemployed. Later, they get jobs at Ken Lau's car garage. Lau's rival, Bluffer Wong, has a competing business that employs young girls as the mechanics.
