The police discover trace the perpetrators of a bank robbery to a group of organized criminals. The criminals attempt to use the sister of a deceased gang member to infiltrate the cops, but when she learns the gang was responsible for her brothers' death, she turns coat and assists the police in foiling the gang's plans.
Cutter Murdock inherits an estate in Africa on which "Satan's Harvest" (heroin and marijuana) is grown. The thugs growing the drugs want him out of the way, so things get messy.
In the Transvaal, in 1900, the British army condemns to death an American mining engineer for aiding and abetting the Boer enemy. The engineer escapes from custody and takes refuge at an isolated Boer farm. When three deserters from the British army arrive on the scene, the engineer takes steps to protect himself and the Boer family.