It's not your typical title for an espionage thriller -- but "The Constant Gardener" (search) has plenty of international intrigue to go around.

Based on the best-selling John le Carré (search) novel, Ralph Fiennes (search) and Rachel Weisz (search) star in this tale of drugs, murder and corruption in East Africa.

"Justin investigates his wife's death and what she was investigating and there's -- people are after him to stop him. They don't want the information to get out, and they will do anything to stop him," Ralph Fiennes said in an electronic press kit.

Shot mostly on location in Africa, the plot isn't as far-fetched as it is in some spy movies.

"It's really about some really important topics that are being debated hotly right now in the media about Africa," Weisz said of the film, which is opening to rave reviews.

Weisz plays the wife of a British diplomat stationed in Kenya who accuses the pharmaceutical industry of exploiting developing nations.

"This plot in this film is based on this particular case in Nigeria -- but it's very usual to test drugs in Africa because it's less expensive for big companies," said director Fernando Meirelles (search), who also directed the Oscar-nominated "City of God."

The Brazilian director jumped at the chance to helm "The Constant Gardener."

"The plot was interesting. It shows how drug companies use Africans as guinea pigs to test their drugs. In return, Africans get free health care -- but they're treated like second-class human beings," he told the New York Post.

As someone who admits "social exclusion" is a running theme in his three feature films, Meirelles goes out of his way to include everyone. Mereilles employed more than 70 Kenyans on the crew, including drivers, caterers, laborers and extras.

"They were just all very excited and happy to participate," he told the Post.

In turn, Africa left a lasting impression on Weisz.

"Nothing was as -- inspiring as Africa itself and meeting the people there and talking to the people and feeling their spirit and their life -- it's vivid, it's such a vivid place," she said.

FOX News' Mike Waco and the New York Post's Lorena Mongelli contributed to this report.