In the kingdom of Vendhya, the king, Bhunda Chand, is in his death-throes, after having suffered through long days of unholy torments. Though the court's healers and priests can find no answer, his sister, the Devi Yasmina, can deduce the cause all too clearly: sorcery of the foulest kind. Her suspicions are confirmed when, during a moment of lucidity, he babbles to her that the fearful wizards of the Black Circle are drawing his soul away, seeking to rend it from his body and use it to breathe life into some daemonic homunculus. At his behest, she is forced to kill him, and for this she swears revenge.
But the Black Seers of Mount Yimsha are known through all of Vendhya, the wizards feared for their terrible powers and unearthly servitors. As beloved as King Chand was and his sister Yasmina is, no man of the Vendyha could be roused to confront the Black Circle. And so, Yasmina hits on a plan; she has the governor of Peshkhauri, the most northerly province of her empire, nestled in the foothills of the Himelians, capture seven headmen of the tribal barbarians who live beyond, seeking to use them as bargaining chips to force the savage and fearless Afguli to wage war on the sorcerers for her.
In this, she succeeds... but her arrogance costs her, for she is present when the Governor of Peshkauri is visited in the night by the current chieftain of all Afguli; Conan, having striven to make of himself the most powerful raider in all of Afghulistan. Realizing he has a golden opportunity, Conan abducts Yasmina and flees for the hills, planning to ransom her back in return for the lives of his headmen.
But Conan and Yasmina both are betrayed; Yasmina's maidservant, Gitara, secretly goes to her lover; the sorcerer Khemsa, an agent of the Black Circle who had been responsible for King Chand's death. The Circle's original plan was to support the ambitions of King Yezdigerd to conquer Vendhya and take Yasmina for his harem, but Gitara, greedy and ambitious, fills her lover's head with ideas of instead betraying both sides to make themselves emperor and empress instead. Madly in love with her, and carried on by her enthusiasm, he goes to the prison and slays the Afghuli headmen before transporting himself and Gitara into the hills in pursuit of Conan and the Devi, determined that they must both die.
Behind them, the Hyrkanian agent Kerim Shah seeks to turn this turmoil to his king's advantage.
Conan and Yasmina take shelter for the night in the village of the Khurum Wazulis, another hill-people whose chieftain, Yar Afzal, owes Conan a life-debt. However, they are forced to flee for their lives after Khemsa's magic slays Yar Afzal and goads the Wazulis into a vengeful fury. Stopping only to buy the clothes from a Galzai hillwoman in order to better dress Yasmina for the trip, they continue making their way into the mountains, only to be attacked by Khemsa and Gitara.
Conan and Khemsa's duel is short-lived when four of the Black Seers arrive. Angry by their student's disobedience, they try to strike him dead with the power of their wills alone, only to be stymied; stronger than they had realized to begin with, Khemsa's love for Gitara is giving him the strength to fight them in order to keep them safe. The moment they realize this, the Black Seers turn their power on Gitara, who is compelled to leap to her death. Before Khemsa can recover from this, they cause an avalanche that sweeps him off the ledge and then abduct Yasmina, leaving Conan behind.
At first just glad to be alive, Conan turns and heads back down the trail, only to be met by his own Afghulis - who turn on him in a fury for having failed to save the lives of their headmen. Forced to flee, Conan turns back up the trail, only to encounter the mangled wreck of Khemsa. The sorcerer clings to life long enough to gasp out some vital clues to defeating the Black Seers to Conan, gives him an enchanted girdle that will protect him from the Seers' sorcery, and then dies.
Thoroughly annoyed with everything, Conan decides to go to the Black Seers' stronghold on Mount Yimsha and recover the Devi. Along the way, he encounters Kherim Shah and a small band Hyrkanian warriors, the last survivors of a band that was ambushed in a pass elsewhere. Driven by a mutual goal, the two forces agree to team up to fight the Seers.
After many battles that sees Kherim Shah's men, and the Hyrkanian himself, slain by sorcerous defenses, Conan manages to kill all of the Black Seers and rescue Yasmina. Heading down from the hills, they discuss where to go from here; ultimately, Yasmina returns to her kingdom, although Conan claims he will one day collect her ten thousand gold piece ransom from her palace in Ayodhya, though Yasmina rebuts that she will instead meet him on the shores of the Jhumda with a hundred thousand men first.
- Action Girl: the Devi Yasmina. She's made of some pretty tough stuff and is not just a wilting lily. She pro-actively seeks her brother's murderers and intends to hire Conan to help her get them. And, when subjected to magical Mind Rape, faints but does not break.
- Always Save the Girl: Conan has absolutely zero interest in challenging the Black Seers of Yimsha. . . until they abduct Devi Yasmina. Conan then states he'll have her back, even if he has to tear the mountain down with his bare hands.
- And Show It to You: One of the Master's spells lets him rip out a man's heart from afar by compelling it to burst from their chest and fly through the air at high speed to his hand. This is how he slays Kherim Shah.
- Arranged Marriage: the Devi Yasmina rejects Conan, despite their mutual attraction, because she says that she must make one for the good of her people. Conan jeers at such a concept.
- Badass Boast: Conan proudly claims to have achieved more things in his life than any average king could hope to have done in an attempt to impress Yasmina into staying with him.
- Body Horror: Khemsa, after being carried down the mountainside by an avalanche. He's essentially nothing but a mass of torn flesh and broken bones in a vaguely human outline, clinging to life solely through a cocktail of The Power of Love and The Power of Hate.
- Break the Haughty: the necromancer's plans for Yasmina, which he attempts by forcing her to live the worst memories of all her previous incarnations, subjecting her to a parade of memories as a lowborn peasant, of a slave, of a mother giving birth, and otherwise experiencing all the indignities and pains of a woman not born into queendom.
- Bring It: At the end of the story, Yasmina tries to offer Conan a ransom for rescuing her. He promises (threatens) to collect his ransom in his own way and time, with fifty thousand men "to see that the scales are fair." Yasmina laughs and promises to meet him with a hundred thousand men. The two part, considering each other a Worthy Opponent.
- Celestial Deadline: The king's murder is governed by this; the spells that the Black Circle are using on King Chand can only function during a certain celestial alignment, after which magical protections woven into the palace will reactivate and shield him from their efforts.
- Dying as Yourself: Yasmina stabs her brother Bhunda Chand on his command to stop the Black Circle from imprisoning his soul in an Eldritch Abomination.
- Dying Moment of Awesome: The opening scene where Bhunda Chand commands Yasmina to kill him while he's lucid, so the evil forces won't get him. She does it, and he dies with a "grim smile". In these few lines, we learn all about Bhunda Chand and mourn his loss.
- Eye of Newt: The king's hair was needed to perform the ritual that ultimately killed him.
- Girl in the Tower: the Devi Yasmina is imprisoned in a tower after being stolen by the Black Seers.
- The Laws of Magic: Referenced during the conversation between Khemsa and Kerim Shah, specifically the Law of Synecdoche, in that it was the theft of lock of hair from King Bhunda Chand that allowed them to begin their work of stealing his soul.
- Men Are the Expendable Gender: Lampshaded by Yasmina; when Conan says she needs new clothes and a peasant girl happens by, Yasmina worries that Conan will kill the girl and take her clothes. Conan says he won't and simply pays the girl. Yasmina is relieved.It was perhaps natural for men to slay and die; her flesh crawled at the thought of watching the butchery of a woman.
- Muscles Are Meaningless:
- Despite being fairly slenderly built, Khemsa's dark magics allow him to deliver immensely powerful physical strikes that even Conan finds hard to shake off.
- One of the Black Seers, even more unimposing than Khemsa, effortlessly shatters a cliff ledge and causes an avalanche to sweep Khemsa away with a casual stamp of his foot.
- Nerves of Steel: Kerim Shah is able to feign unconsciousness while Khemsa and Gitara are feet away and arguing about killing him.
- Our Homunculi Are Different: During the opening, the King declares that the Black Seers have summoned up some "homunculus from hell" that they wish to bind his soul to in order to give it life, a fate so terrifying he begs his sister to give him a Mercy Kill instead.
- Past-Life Memories: The mechanism through which the Master of the Black Seers inflicts Mind Rape on Yasmina.
- Redshirt: When Conan and Kerim Shah agree to an alliance to rescue Yasmina, several of Kerim Shah's men come with them. Their main function is to be killed so we can see the Black Seers' magic in action.
- Revenge Before Reason:
- Yasmina is so outraged that the Black Seers would attack her brother that she becomes determined to slay them all in revenge, despite being well-aware of their infamous reputation and their terrible powers.
- Averted; when Khemsa betrays Kerim Shah, the Hyrkanian is simply relieved that the sorcerer didn't kill him before leaving and casually turns his mind to turning the situation to his advantage.
- Royal Blood: Yasmina is proud of hers.
- Royals Who Actually Do Something: Yasmina. She bravely goes alone to the Peshkauri governor's place with just her maid, to describe her plan to get Conan's help. Later, when she hears the horns of the Vendhyan army looking for her, she immediately demands Conan's horse, rides to them and leads them to fight the Turanians.
- Sacred Hospitality: When Gitara goads Khemsa into turning on his masters and abandoning their plan to support Kerim Shah, he refuses to kill the Hyrkanian, commenting that he has "eaten his salt" as justification.
- Scaled Up: The Master of Yimsha fights Conan in this fashion. Indeed, it does not help.
- Shockwave Stomp: One of the Rakhshas uses this to cause the avalanche which ultimately claims Khemsa's life.
- Smooch of Victory: Yasmina passionately kisses Conan after he rescues her from the Master of Yimsha. That's as far as she's willing to go, however.
- Somewhere, a Herpetologist Is Crying: When the Master of Yimsha Scales Up to attack Conan, he tries biting him with venomous fangs. Conan draws a dagger and pins the giant snake's jaws shut, so it attacks with "the only weapon it has left"... trying to constrict Conan to death. This is a magically shape-shifted snake.
- Villainous Valor: Khemsa is an evil wizard in a Conan story, so of course he is doomed, but he is also the best-developed such character Howard had created up to this point. His lover, Gitara, induces him to betray his masters, the Black Seers of Yimsha, (just as she has betrayed her mistress, Yasmina,) in the hopes that the two of them can conquer an empire together. When he does, they retaliate, and four of them bring their full sorcerous might down on him. But his love for Gitara is genuine and allows him, in defense of both himself and her, to draw on a strength of will not even he suspected he possessed. For a time, he is able, alone, to withstand the power of the four together. Unfortunately, one of them recognizes the source of his newfound strength and forces Gitara to throw herself from a cliff. This breaks Khemsa's will and allows them to defeat him. When Conan finds him later, broken but still alive through a combination of his magical power and burning desire for vengeance, he gives Conan the means to defeat the Black Seers. Khemsa is so remarkable that it's probably best the story didn't end in a showdown between him and Conan, because some readers might have found it rather difficult to root for the Cimmerian by that point. It's not like Conan never betrayed anyone to get what he wanted...
- Voluntary Shapeshifting: In addition to getting Scaled Up, the Master of Yimsha takes the form of a giant vulture for a last-ditch attempt on Yasmina.
- World Building: After fleeing from the Wazulis, Conan mentions the black bead that was given to Yar Afzal reminds him of the beads worn by the dancers in the temple of the Spider-God of Yezud, and that the spider which killed the chieftain looked like a much smaller depiction of that abominable arachnid deity. This story would later be fleshed out by L. Sprague de Camp in the novel Conan And The Spider God.