Hearing of a native uprising at the African Copper Mines at Karanga, manager Edmund Daniels and American counsel Jeff Worthing catch an arms-and-ammunition bearing train. Other passengers include Paul Stacco, a sort of native white god expected to settle the rebellion peacefully; Daniels's secretary David Wallace; Dr. Greenleaf and his nurse Julia Garrett; Steve Harley, a young American adventurer; Manek Sen, a mysterious Eurasian; and Slats Breese, an American fight trainer. Daniels is murdered on the train and an investigation reveals that Dr. Greenleaf's real name is one notorious in medical circles, and that Manek Sen is set on killing Hawley to get the latter's treasure maps. Daniel's papers are found in Stacco's possession. Julia is wounded when the natives, under Stacco's orders, attack the train. Later, Jeff exposes Wallace as Daniels' killer, as Daniels had discovered he had been stealing from the mine.