Shin (Jacky Cheung) and Chiang (Stephen Tung Wai) are happy-go-lucky partners investigating a particularly notorious crime syndicate. Unfortunately, Shin’s Mainland relatives — Cha Chiang (Alfred Cheung Kin-ting) and his beautiful sibling Cha Shi (Loletta Lee Lai-chun) — decide to drop by. While Chiang insists on accompanying his cousin on the job, Shin starts to make eyes with Shi. Meanwhile, Chiang runs into his ex-girlfriend Nancy (Bonnie Fu Yuk-ching). When Nancy witnesses a gangland hit, she and everyone around her are threatened by the mob.