Two prospectors in Africa, Tony Cooper and Dalton come across a skeleton that has nearly been picked clean by vultures. They find a letter on the body addressed to a clerk in London named Wilkins . Cooper goes to Wilkins in London and tells him that his brother, whose body they had found, has left a map and a deed to a large diamond mine. Wilkins decides to go to Africa with Cooper to find the mine and, in order to speed up and finance their venture, they give a third interest to Carol Reade and her partner John Trevor), who operate a barnstorming airplane service. In Africa, close to the mine location, they are greeted by some tough gentlemen named Collins and Quincy who have terrorized the natives and lorded over the region, who quickly discover the reason for the party's mission. They join, unasked, in the race for the diamonds. The race is interrupted by the death of Trevor who is found knifed in his bunk.
