A rapturous urgency drives The Constant Gardener, an immensely satisfying thriller-romance that tells the story of a too-silent marriage on the expansive canvas of a too-silent global problem.

Director Fernando Meirelles (City of God) turns his frenetic camera’s raw observance on Kenya, brought to life with a color palette on steroids. (The film’s sound design is equally dynamic, from the sickening hum of morgue lighting to the thundering chug-a-chug of trains).

In exploring a populace in denial of its AIDS problem largely because it’s denied medical competency, this isn’t another case of Hollywood safely kissing boo-boos of the world from far away. It’s a high-pressure squirt of peroxide on a fresh, open wound. One character’s line, “We’re not killing people who wouldn’t be dead otherwise,” cuts as deeply as Nick Nolte’s line about where Africans stand in the global hierarchy in Hotel Rwanda.

Handheld-camera views from street level shove the effects of poverty and sickness in the audience’s face, suggesting that new blood will drip just as old lashes permanently scar over. And through an uncharacteristically dramatic turn from Bill Nighy (Love, Actually), the movie even probes the self-told lies believed by those isolated from wrongdoing through their political power.

Wrapped up in this is the tale of a marriage between two people who would seem to have nothing in common but for their crucial connection of compassion. In these roles, Ralph Fiennes and Rachel Weisz deliver some of the finest performances of their impressive careers.

The film offers instant disorientation with a wrecked Jeep’s jarring plop-down on a remote desert road and an explanation of what that means for Justin Quayle (Fiennes), the Minister of Aid Effectiveness to the British High Council’s interests in Africa.

One of its brutally slain passengers was Tessa (Weisz), his antagonistic, outspoken human-rights activist wife. In a burning, internalized moment, Fiennes’ ashen face expresses less grief over the news than it does over the mental burden suffered by the colleague who relays it to him.

Justin’s superiors declare her murder a crime of passion committed by her now-missing doctor friend (Hubert Kounde), who was her traveling companion. Rumors of Tessa’s infidelity nag Justin, and he feels remorse at emotionally betraying her through insecure suspicions he harbored before her death. As he investigates a widening trail of shady circumstances, Justin discovers both a conspiracy that links colonialism and commerce and the truth about his enigmatic wife.

Part of the film’s brilliance is in its non-linear layout, and the cleverly fragmented story toys with the viewer’s perceptions. Some of them will be right, most of them will be wrong; all of them are masterfully manipulated in an intoxicating way.

Adapted from John Le Carre’s novel, Jeffrey Caine’s screenplay also nails a 1970s style of paranoid suspense from the notion that Justin could suffer snatch-and-grab disappearance at any time. Pulse-quickening claustrophobia sets in during a close-quarters hotel-room attack, as well as an SUV chase in the desert and a nomadic tribe’s raid on a remote medical outpost.

No bones about it, The Constant Gardener requires a degree of patience. But it’s rewarded with a resolutely satisfying conclusion. Its power comes from dignity and restraint, as well as the highpoint of the lingering spell Weisz casts over the entire movie in her flashback moments.

Diplomacy isn’t so easily cultivated in the world’s larger, more dangerous gardens. Just as its lead character breaks free from his comfort zone, so does Meirelles from traditional thriller trappings. The vivid vigor with which he does so makes this 2005’s best film so far.