Not my cup of tea, sorry. This is a manipulative political thriller, based on a John le Carré novel, where a handful of saints go up against a conspiracy involving corrupt British officials in league with a couple of murderous international drug companies. It's set mainly in Kenya. Rachel Weisz plays Tessa, who is murdered early in the movie, but keeps showing up in flashbacks. The movie revolves around her husband's (played by Ralph Fiennes) efforts to pierce the coverup erected by the conspirators, and to find out what Tessa was up to. The ending is bleak.
The acting is first-rate, and the director, Fernando Meirelles, is the same guy who did City of God, and he does as good a job of depicting African squalor as he did Brazilian squalor. The critical praise for the movie seems mainly based on its wise choice of villains, primarily drug companies. Corrupt African officials are brought in mainly as window-dressing; the United Nations folks, as near as I can tell, are uniformly honest and hard-working.
I will not be holding my breath to see an equivalent movie based on a more realistic premise of UN corruption.