In 19th century Hong Kong, the local marine police and the regular police are at odds over who should handle piracy troubles that plague their waters. A dedicated marine officer, Dragon Ma, is exasperated by the infighting and lack of resources as pirates continue to threaten trade routes. Despite his best efforts to maintain discipline, tensions arise when rival officers sabotage training exercises, and the introduction of new recruits adds to the chaos. Meanwhile, Dragon Ma develops a wary alliance with a clever streetwise thief named Fei, who has his own problems with local thugs and a racketeering gang that wants to encroach on his territory.

As Dragon Ma grows frustrated with bureaucracy and failed plans, his determination leads him to tackle the pirate threat head-on. Fei, with his quick wit and street skills, unwittingly joins this mission after their paths cross again in a chaotic brawl. Together with loyal allies within the marine police, they work outside the confines of their offices to mount an assault on the pirate stronghold. As obstacles mount, including betrayals and strategic blunders, Dragon Ma must navigate treacherous waters, literally and metaphorically, to dismantle the pirate operation and restore peace to the seas. As preparations for the final showdown unfold, tensions reach a boiling point, setting the stage for explosive confrontations and daring action sequences.