Set in the 6th century AD Early T'ang Dynasty, on the remote Silk Road, Western frontier trade route, Warriors of Heaven and Earth concerns the safety of a camel caravan and its cargo: a beautiful, small, golden, multi-layered casket protecting priceless, mystical Buddhist relics. These items confer great power and influence on whoever possesses them, motivating the T'ang emperor's efforts to prevent an equally covetous, notorious Turkish bandit chief from stealing this treasure, the valuables being en route from India and now traversing the Gobi Desert region.

When a sandstorm wipes out all the expedition's guardians save for the monk (Yun Zhou) directly supervising the precious artifacts and Zao Zimou (Li Hai-bin) a soldier, the latter, seeking replacement escorts in an oasis settlement, hires without inquiring about his past, Lieutenant "Butcher" Li Zai (Jiang Wen), a former officer of the Imperial army who some years before, went AWOL rather than kill war-captive women and children. A mercenary ever since, along with the small group of loyal buddies who renegaded with him: Wu "Long-haired Scorpion" Lao-er (Liu Linian); Ma "the Lantern" Gun (Ho Tao); Bai "Horseshoe Maker" Tuzi; and Cao "One-eyed Eagle" Jian (Hasi Bogen) - Li and these men, between jobs, keep a home base in nearby Western Lake. Li and company, accepting the soldier's offer, bolster their number by signing on two more guys: teenager Lizard and a feisty elder, "Old Die Hard" (Wang Deshun). The new guardians learn of their mission's true value, somewhat later in a revelatory scene crucial to the plot, while journeying to Changan, capital of T'ang China.

Adding complications to the story, after all these years, Li Zai, still wanted for dereliction of duty, becomes the target of the Emperors emissary, Japanese-born Lai Xi (Kiichi Nakai) who, for his last assignment before being permitted to return home after a 25 year absence studying Chinese culture and martial arts in the royal employ, must track down and execute the ex-officer. Accompanying Lai Xi - his ward, a T'ang general's intelligent, brave, orphaned daughter Wen Zhu (Vicky Zhao Wei), also functions as intermittent voice-over narrator/commentator of the proceedings.

Lai Xi and his quarry's paths cross in a way-station town "Big Steed Village" where Lai's skillful defeat of a local trouble-maker impresses and arouses the hostile interest of the settlement's warlord Master An (Wang Xueqi), an expert fighter and superb, frequent er-hu (Chinese stringed-instrument played with a bow) musician and none other than the wanted Turkish villain mentioned previously. After a thrilling sword duel that ends in a draw, Lai Xi and Li Zai call a truce, agreeing to team up to protect the caravan until the mission gets accomplished, after which they will resume the conflict.

During the rugged trek involving many grueling and exciting struggles with An and his forces, (a skirmish in a canyon being a real stand-out), each of the protagonists' personalities emerge distinctly and memorably in scenes of wit and poignancy, so that when not everyone survives to the end - the loss gets keenly felt. This fine mix of action and character development (including a veiled attraction between Wen Zhu and Li Zai), persists right up to the climactic showdown in a deserted fortress. There medieval military strategy and tactics get well depicted, including the shooting of flaming arrows for defense and especially the Chinese use of masses of rocket-propelled arrows fired from rolling carts, a unique armament deployed in this period of the first invention of gunpowder. Plenty of fighting occurs involving the opponents' cavalry attacks, and involving both sides wielding hand weapons such as sabers; straight swords; long bows; cross bows; and maces - all the movements being realistic (no flying at all) and often bloody. Clever close-up camera work effectively conveys the confusion of battle while panoramic long shots reveal what's happening more clearly.

A literal deus ex machina ending, the film's one glaring flaw, concerns the sacred Buddhist objects in a CGI effects sequence straining the credulity amidst the gritty realism that had mostly gone before. Far outweighing this fault, the rest of the production makes everything well worth seeing particularly for the superb performances, especially between the stars portraying the relationship between Li Zai and Lai Xi as they cope with that age-old dilemma of feelings interfering with duty. Master An makes a delightfully eccentric and formidable antagonist. Wen Zhu, getting one brief Amazonian moment at the conclusion, deserved a bigger part and so did the rest of the supporting players.

The spectacular locations so dazzled, they served as a character along with the people. Splendid sets; lovely costumes and hairstyles; interesting armor; vivid local color; excellent action set pieces - all make this picture a visual treat while A. R. Rahman's atmospheric, distinctive score enhances everything. Warriors of Heaven and Earth set in China's "Old West" - must not be missed by anyone who loves historical period martial arts or by folks who crave glorious, epic adventure in general.