Running on Illegal Fuel and Savage Zeal "Drug War," Johnnie To's ferocious crime story, opens with bilious green smoke darkening the sky and ends with a tsunami of blood spilling onto the ground. The green billows out of an illegal meth lab that has exploded while the red pours from the dead and the dying who, throughout this excitingly directed movie, have chased one another as if to the ends of the earth. If the green smoke suggested "go," the blood can only mean one thing: "stop," which, taken with the surrounding human wreckage, serves as an unmistakably fierce authorial commentary. The same can be said of all the savagery wedged between the smoke and the blood. Effectively a feature-length chase sequence interrupted by moments of weird comedy and interludes of savage violence, the story and its sympathies are neatly split between bad guys and good, a narrative and emotional divide that has an unsettling effect, much like the crazed yet scarily controlled laughter of one of the villains. And while Mr. To may not fill the movie with rousing speeches, either by inclination or out of political necessity, the brilliant, unsettling action scenes - ugly, savage, dehumanizing - speak volumes. This is one of the rare times that the Hong Kong master has shot on the mainland, and if he faced any pressure from China's censors to soften his material, it isn't evident to an outsider. The characters are introduced rapidly, as is Mr. To's fashion. Among the principals are Timmy Choi (a great Louis Koo), a drug kingpin first seen driving away from the meth lab, barely holding onto the wheel as he begins to literally foam at the mouth. It's instructive that his law-enforcement counterpart and narrative double, Captain Zhang (Sun Honglei, fantastic), is also introduced while in transit, aboard a bus loaded with contraband, and that he's initially under cover pretending to be a criminal. Choi and Zhang may be racing forward - all the characters rack up miles, their spinning wheels turning this into something of an intermittent road movie - but they never seem to get far enough. Round and round they go in a relentless chase that soon feels like a circle. It can take some doing to figure out who's going where and why. Mr. To likes to play with austerity and overload, sometimes mercilessly so. The sheer number of characters zigzagging through the beginning of "Drug War" - many behind a wheel - means that sometimes you just need to go with the flow and worry about what's happening later. That's a nice change from movies that needlessly hold your hand through every turn, but it also means that you shouldn't blink. If you do, you may wonder who the two scruffy guys are in the car that's chasing the big truck that's being driven by two other disheveled guys who seem to have something to do with Choi, whose path and fate will soon cross with those of Captain Zhang, once this heroically peripatetic detective gets off his bus. He does and, after bringing down someone with a high-flying scissor hold, brings you into a complicated tale that reaches from the crime lords who imperiously flaunt China's draconian drug laws to the struggling men and women who in an earlier age would have been slaving over the emperor's lands. That in itself is startling, as are so many of the details - a detective washing recently excreted balloons stuffed with drugs - that insistently underscore the human stakes in this war. Among the most unexpected moments in a movie filled with them is the group of sympathetically drawn deaf, mute drug workers. Whether laughing or sharing a convivial meal in a factory crammed with drugs, they are the manifestation of a people who, Mr. To bluntly suggests, must be heard. Drug War Directed by Johnnie To; written by Wai Ka-Fai, Yau Nai Hoi, Ryker Chan and Yu Xi; director of photography, Cheng Siu Keung; edited by Allen Leung; music by Xavier Jamaux; art direction by Horace Ma; costumes by Boey Wong; produced by Johnnie To and Wai Ka-Fai; released by Well Go USA and Variance Films. At the IFC Center, 323 Avenue of the Americas at Third Street, Greenwich Village. In Mandarin, with English subtitles. Running time: 1 hour 45 minutes. WITH: Sun Honglei (Captain Zhang), Louis Koo (Timmy Choi), Huang Yi (Yang Xiaobei), Gao Yunxiang (Xu Guoxiang), Wallace Chung (Guo Weijun), Li Guangjie (Chen Shixong), Lo Hoi Pang (Birdie) and Cheung Siu Fai (Su).