I'm glad I gave this another chance before writing this review. After a second viewing, I have to admit this semi-adaptation of King Solomon's Mines is better than I first gave it credit for, even if I still don't think it's that great of a movie.
Set in Africa, 1897 (because of course the whole continent is just one big country, right?), we open with Allan Quartermain (Stewart Granger) taking a pair of hunters on a hunting safari. The expedition ends badly when one of Quartermain's bearers is killed saving the life of one of the hunters - while said hunter was running away like a coward. Saddened by the loss of his friend, who he's known for eight years, Quartermain's gotten tired of the hunting business. He considers leaving Africa altogether and returning to England to be with his young son, who was sent to boarding school after Quartermain's wife died. However, a newly arrived Englishman named John Good (Richard Carlson) seeks to enlist Quartermain's help for one last expedition. His sister Elizabeth (Deborah Kerr) is searching for her husband, Henry Curtis, who went missing some time ago on a hunt for King Solomon's fabled diamond mines. Quartermain deems it an impossible venture, and distrusts Elizabeth's motives. However, when Elizabeth makes an impassioned plea and offers him a great deal of money - enough to allow his son to live comfortably until he becomes an adult - Quartermain gives in. From that point on, the film becomes a series of random encounters, including with various jungle beasts, a fugitive diamond smuggler (Hugo Haas), and a member of the Watussi tribe named Umbopa (Siriaque) - yeah, no fictional Kukuanaland in this film.