Two years ago, hunting guide Mike Davis was with a client who trespassed on diamond company land and found a rich lode; Paul Vogel, sadistic commandant of company police, beat Mike nearly to death but failed to learn the location. Now Mike is back in Diamantstad, South African desert, and manager Martingale has a better idea: he hires delectable adventuress Suzanne to ferret out Mike's secret. But she soon finds she's playing with fire.

The Diamanstad police of the South African desert work for the Colonial Diamond Co., and are commissioned to track down thieving employees attempting to escape through the sand dunes. The brutal police commandant Paul Vogel even scrutinizes his prisoners' open flesh wounds, in which he often discovers secreted diamonds. The return of American game hunter Mike Davis, after a two-year absence, infuriates Vogel, who has vowed revenge against Mike for an old transgression. Vogel savagely takes out his hostility on John, a black dock worker, and Mike comes to John's aid and befriends him. Vogel reports Mike's return to Fred Martingale, and the devious, wealthy manager of Colonial insists that Vogel refrain from any action until Mike's intentions are known. Later that night, Suzanne Renaud, a beautiful nightclub dancer, attempts to seduce Martingale, who instead hires her to seduce Mike and determine the location of his secret diamond cache. At a seedy café, Mike is approached by Toady, an opportunist who believes that Mike has returned to collect the diamonds that Vogel once tried to torture him into giving up. Suzanne also approaches Mike, but he sees through her cheap manners and snubs her. Vogel, however, is smitten by Suzanne, and becomes enraged when Mike insults her. Instead of fighting, the rivals compete in a poker game, and Vogel wins by cheating. Suzanne goes home with Vogel, but is repulsed by his ruthless acquisitive nature. Mike then breaks into Vogel's house and recovers his money as well as Suzanne, thereby beating Vogel at his own game. On the drive back to Diamanstad, Mike succumbs to Suzanne's charm, and recalls the source of his old feud with Vogel: While on a lion hunt, Mike's client, Ingram, sneaks off alone into an area of desert owned by Colonial. Mike follows Ingram's tracks for miles in the relentless desert heat until he finds Ingram, who has discovered a bushel of raw diamonds. Forced to shoot his dehydrated horse, Mike leaves the diamonds, and carries the dying Ingram back to town. Vogel brutally beats Mike to discover the location of the diamonds, but Mike refuses to talk, and barely survives his torture. Mike has now returned for the diamonds, which he feels he paid for with the beating, and Suzanne, who has fallen in love with Mike, is unable to talk him out of it. Using information from his alcoholic friend, Dr. Francis "Doc" Hunter, Mike later befriends Thompson, a disgruntled Colonial guard, and secretly plans for Thompson to take him into the prohibited area. When Suzanne firmly rebuffs Vogel in favor of Mike, Vogel becomes even more determined to ruin him, and forces Thompson to reveal their plan. Mike senses a set-up and refuses to go through with his rendezvous with Thompson, but Vogel arrests him anyway and brutalizes him, until Martingale orders his release. Vogel complies only after Suzanne threatens to make public his marriage proposal, which could ruin his reputation. Mike convalesces for as long as his patience allows, then puts his faith in Suzanne, who has secretly promised to tell Martingale the location of the diamonds in exchange for Mike's life. When Mike sees confirmation of Suzanne's apparent duplicity, he leaves immediately, and ambushes Vogel on a desert road. During their struggle, Vogel accidentally shoots his own guard. Mike takes Vogel hostage so that he can pass the police check point, then dumps him in the middle of a sandstorm. Mike digs up his diamonds and drives across the border into Angola, while Vogel struggles back to Diamanstad. Enraged by his defeat, Vogel accidentally kills Hunter while arresting him for complicity, and covers up his blunder by arresting Suzanne for Hunter's murder. In Angola, Mike learns of Suzanne's plight from Toady, and finally takes up Toady's offer of assistance. Mike returns to Diamanstad and confronts Martingale, offering to trade the diamonds for Suzanne. Martingale is amused by the thought of thwarting Vogel, while at the same time appearing the "hero" to his company. At Martingale's office, Mike forces Vogel to sign a statement claiming Suzanne's innocence, and Vogel realizes too late that this implicates him as Hunter's killer. The duplicitous Martingale helps Vogel defend himself, but warns Mike, who then kills Vogel as Martingale had hoped. Later, when Mike learns that Suzanne tried to save his life, he pledges his love to her. Before their boat leaves the dock, Martingale gives Mike three of his diamonds as a gift, and Mike bestows one upon John, who has become a steadfast friend, and one to Toady as thanks.