The Constant Gardener might find itself taking the spot held last year by Hotel Rwanda. Both movies are issues-spotlighters, with each of their subjects dealing specifically with African plights. In this year's movie, attention is brought to the questionable testing practices of pharmaceutical companies, which result in mistreated and lost African lives, the less rosy details of which are swept under the rug in the name of the almighty profit.

What The Constant Gardener lacks, however, is something equatable to the inspiration and fire communicated by Don Cheadle's performance in Hotel Rwanda. It offers something close in the guise of Rachel Weisz, the activist wife of a passive British diplomat, Justin Quayle (Ralph Fiennes), who ostensibly embodies the name of the film. Weisz plays Tessa, an outspoken bleeding-heart liberal, the kind that would challenge a lecturer to a debate while causing everyone else in the audience to either squirm uncomfortably or shuffle out in disgust. But Justin sees in her the yang to his yin (yes, it's a strange metaphor to use, since yin is considered to be the "female" side) and promptly engages in a relationship with her that leads to marriage.

Weisz is a firecracker in this role, driving much of the movie's push and pull. Unfortunately, she only gets to be in half the movie because, well, as the film starts, Tessa is killed. Following this revelation is a section of flashbacks, which provide the backstory of Justin, Tessa, and the company they keep during their trip to Kenya. Details include Justin's developing relationship to Tessa and Tessa's own mysterious relationships to others as she continues her activist work. The idea is to build up to the mystery that Justin will work to solve in the movie's second half.

The Constant Gardener is really trying to be two things. On the surface, it's a romantic thriller about a man uncovering a conspiracy that may have led to his wife's murder, and for its first half it succeeds in being involving as this. The second half, though, loses steam as Justin's discoveries successively lose impact, due to their rather mundane obviousness. This is  because the movie's deeper purpose has asserted itself -- it's primarily about powerful government and corporate injustices slapped down on third-world countries. In testing health-related products, the big businesses jeopardize the very well-being of the populace of their testing regions. The movie concerns itself with just how far they are willing to go.

Director Fernando Meirelles gave us City of God, a movie I admired that was praised much more highly by many others. I thought that movie's style was superb, but didn't feel it reconciled well with its subject matter. Ironically, The Constant Gardener helped me to better appreciate what made City of God work the way it did -- regardless of how much the style fit the subject, it was energetic and, along with the story, very involving. In Gardener, Meirelles tries something similar, but not as flashy -- he tries to create a freneticism out of the constant use of handheld photography. It creates a sense of paranoia and claustrophobia, but it begins to feel excessive as the air is being let out of the tires of the second half.

It's a valiant effort to give an essentially quiet thriller with a quiet leading man a visual flair, but this time the incongruity of style and subject feel more conspicuous, as there is less excitement and dramatic energy in the narrative to help propel it. A combination of things leads to the film's general feeling of winding down -- Weisz leaves a void that Fiennes can't make up for by himself, and the story becomes less concerned with the characters it created, giving the feeling of favoring its "message." Message movies are a hard sell in general, but, like Hotel Rwanda and last year's The Motorcycle Diaries, there's enough here that's recommendable, including witnessing the work of a director who, so far, is willing to take his camera to areas of the world that most people in "civilization" would rather not know about. Even if it doesn't run entirely smoothly, The Constant Gardener carries a nobility in its purpose that's worthy of attention.

(Released by Focus Features and rated "R" for language, some violent images and sexual content.)