Alongside DiCaprio, who plays a diamond-chasing mercenary with an annoying accent, the movie stars Djimon Hounsou as a fisherman whose family was caught up with a rebel group involved in diamond-mining; his character was briefly enslaved, during which time he hid a huge-ass diamond somewhere. Oh, and Jennifer Connelly is there, too. According to the AICN reviewer, she plays "a cliched American knockout journalist with an edge" who spends the movie -- during which Hounsou and Leo go after that hidden diamond, and Hounsou tries to find his family -- "just kind of [cheering] them on while bemoaning the injustice of it all." (Unsaid, of course, is "But she's hot, so no one will really care.")
That said (and despite the fact that the current edit is nearly three hours long), the reviewer liked the movie. He was particularly impressed with Hounsou, who he says out-acts DiCaprio at every turn; the movie would be a lot better, apparently, if DiCaprio's character was trimmed down, and the film was allowed to focus on Hounsou, and his struggle to find his family. In addition, the report says the movie is crazy violent -- ala Total Recall, if you can believe that (though since an ENTIRE PLANET DIES in Total Recall, I think we're safe in assuming the body count is at least slightly lower) -- but fails to mention whether or not Connelly takes her clothes off.