Burton, the more experienced explorer, heads the expedition. His tribal language skills are good but Speke's willingness to hunt for game and his greater focus on the mission are of equal importance.
Their 1856 to 1859 expedition is ultimately successful, but at considerable personal cost. Tropical diseases force Burton to be carried by bearers, while Speke becames loses his hearing in one ear after a beetle crawls into it and he attempts to remove the intruder with a knife. Along the way, they free a slave (Delroy Lindo) who fears that the expedition will lead him back into servitude.
While Burton is incapacitated with illness and held prisoner by an immature and impetuous local warlord, Speke travels north with a small party and discovers a massive higher elevation lake, which he names after Queen Victoria. Speke believes this must be the source of the Nile, but lacks the scientific skills to prove this.
Burton and Speke separately return to England and became bitter rivals, publishing books with opposing theories. Burton marries Isabel (Fiona Shaw), a headstrong woman determined to have him. Speke is gay and apparently has a relationship with Larry Oliphant (Richard E. Grant), a publisher who encourages Speke to libel Burton.
Speke has a second expedition to Lake Victoria but is again unable to prove it is the source of the Nile. Burton is the better writer and scientist and gains the upper hand in the controversy surrounding the explorers. A debate is scheduled between them to "decide" the matter, but Speke commits suicide the day before during a hunting party. A number of years later, another expedition confirms Lake Victoria is the Nile source, thus Speke was correct and Burton was wrong, after all.
How others will see it. Characterized as an art house movie, Mountains of the Moon was praised by critics but made little commercial impact. It was ignored by most film festivals.
Today at imdb, the movie has an unimpressive 2.5K user votes. The user ratings rise moderately with advancing age of the viewer, from 6.9 under age 30, to 7.4 over age 45. Most viewers appreciate the sense of credible adventure from their joint expedition, and commiserate with the many hardships endured by the duo as they encounter hostile tribes, tropical disease, and hungry lions.
How I felt about it. I had seen the movie twenty years before, and the one scene that I remembered from it was the bug crawling into Speke's ear, driving him to temporary madness from pain and terror. One wonders, while seeing it again, how any explorer made it to the heart of Africa without the support of an army, and why anyone would voluntarily endure such hardships merely in the hope of securing contemporary fame and a footnote of history.
It is interesting that Burton doesn't return to the continent he loves, Africa. But he has an adoring wife to keep him in civilization, and he is discredited by controversy. The personalities of outgoing Burton and introverted Speke are contrasted, but it appears that their greatest accomplishments happened when they worked together as a team.