The novel is set in the Underdark, a vast subterranean world beneath the earth's surface. Ten years after fleeing the drow (dark elf) city of Menzoberranzan to escape its cruel society, Drizzt Do'Urden has devolved into a primal survivor he calls "the hunter," prowling the tunnels on instinct alone. His sole companion is Guenhwyvar, a magical panther summoned through an onyx figurine from the Astral Plane, a separate realm where the panther resides. After killing a basilisk that invaded his territory, Drizzt feels ashamed at his savage triumph. He fears that losing the ability to speak will prevent him from summoning Guenhwyvar, and solitude will consume him entirely.
In Menzoberranzan, Matron Malice Do'Urden, Drizzt's mother and ruler of House Do'Urden, concludes a decade-long covert war with rival House Hun'ett, aided by Jarlaxle, leader of the mercenary band Bregan D'aerthe. Matron Baenre, the city's most powerful figure, forces Malice to adopt SiNafay Hun'ett, the defeated matron, as a new daughter and warns that Malice must regain the favor of Lolth, the Spider Queen deity, on her own. Years earlier, Malice had sacrificed Zaknafein, Drizzt's father and beloved mentor, to appease Lolth after Drizzt refused to embrace drow cruelty. Drizzt's flight cost the house both its weapon master and Lolth's favor. Malice commands her family to find Drizzt.
Briza, Malice's eldest daughter, leads a hunting patrol into the Underdark with Dinin, the house's eldest son. They track Drizzt using a spell attuned to his house emblem. Drizzt detects them, gives the emblem to Guenhwyvar to split the patrol, then ambushes his siblings. He overpowers Dinin and duels Briza, destroying her snake-headed whip. As he moves to kill her, Guenhwyvar tackles him and dismisses itself back to the Astral Plane, judging his savagery. Shaken, Drizzt confronts the realization that the hunter is consuming him. Meanwhile, drawn by the sound of voices, he has been following svirfneblin (deep gnome) miners toward their city, Blingdenstone, but twice cannot bring himself to enter. Convinced that survival alone is no longer enough, he surrenders at the city gates, dropping his weapons at the guards' feet.
Back in Menzoberranzan, Malice's family acknowledges that Drizzt's wilderness skills exceed their ability to capture him. Malice summons a yochlol, a handmaiden of Lolth, and requests Zin-carla, the Spider Queen's greatest gift: the animation of a corpse with the deceased's spirit and combat skills, controlled by the matron mother's will. A casket reveals Zaknafein's decomposed corpse. The yochlol demands a great sacrifice, and Malice drives the ceremonial dagger into SiNafay Hun'ett, delighting Lolth. Over 70 days, the family creates a spirit-wraith, an undead being with Zaknafein's fighting prowess under Malice's control, and sends it to hunt Drizzt.
Inside Blingdenstone, Drizzt faces execution until he mentions a deep gnome he once saved, one who lost his hands. The svirfnebli recognize the name: Belwar Dissengulp, the Most Honored Burrow Warden, a distinguished title among the deep gnomes. Belwar vouches for Drizzt, and the death sentence is reversed. Over subsequent tendays (periods of 10 days), Drizzt reintegrates into svirfneblin society, though the hunter sometimes erupts violently. He challenges Belwar, a recluse burdened by guilt over a past mining disaster, to rejoin expeditions. Belwar proves himself on a successful trip, regaining his confidence. His mithral prosthetic hands, crafted from a rare silvery metal and enchanted with the command word "Bivrip," can mine stone with explosive force.
The spirit-wraith's slaughter near Blingdenstone raises alarms. King Schnicktick's spy network learns that House Do'Urden is hunting its renegade son, and the king reluctantly expels Drizzt to avoid war. Belwar appears at the gates with a packed bag, refusing to let Drizzt go alone.
The companions head west, setting a false camp to mislead pursuers. They survive hazardous terrain and an attack by a human wizard named Brister Fendlestick before settling in a defensible cave beside an underground lake. Near their new home, Drizzt encounters a hook horror, a huge armored bipedal monster, that astonishes him by speaking halting drow. The creature, which they name Clacker, was once a pech, a small, peaceful, stone-loving being, transformed by Fendlestick's magic. Belwar warns that the polymorph spell will eventually consume Clacker's pech mind entirely. They track the wizard to his tower and force him to open the door, but Clacker kills the wizard in a rage before the counterspell can be cast.
The spirit-wraith reaches the lake cave and pursues them west. The companions enter a region where illithids (mind flayers), telepathic creatures with octopus-like heads that feed on brains, ambush them with stunning mental blasts. All three are captured and enslaved: Clacker as livestock keeper, Belwar as a gladiator, and Drizzt as attendant to the community's central brain, a pulsating mass of flesh that coordinates the illithid hive mind. Their identities are submerged beneath mental domination.
The spirit-wraith attacks the illithid lair, immune to their mental blasts. On the Astral Plane, Guenhwyvar attacks two observing illithids and rides one back to the physical world, materializing inside the lair. The returning memory of the "Bivrip" enchantment and the sight of Guenhwyvar jolt Belwar free of mental control. Guenhwyvar tears apart the central brain, and the psychic shock shatters every illithid's hold on every slave. Drizzt regains his identity, recovers his scimitars, and fights free. The companions escape through iron doors, but Drizzt spots a lone drow warrior cutting through illithids with unmistakable swordsmanship and whispers the name: Zaknafein.
Drizzt rushes toward his father, but the spirit-wraith attacks, speaking in Malice's voice. Drizzt recognizes Zaknafein's authentic fighting style within the monster. An illithid stuns Drizzt from above, and as the spirit-wraith closes in, Clacker experiences a surge of pech consciousness and conjures a stone wall between them, saving Drizzt. The companions flee.
Heading back toward Menzoberranzan to find a wizard who can reverse Clacker's polymorph, the companions reach an acid-lake cavern. Clacker's pech identity has been fading rapidly; he begs to be killed, but Drizzt refuses. The spirit-wraith arrives first and strikes Clacker down. Zaknafein steps onto the walkway to face Drizzt. Their swords clash as Drizzt tries to awaken Zaknafein's buried consciousness through familiar training routines. He executes a well-known combat sequence; the spirit-wraith anticipates the counter perfectly, confirming that Zaknafein's spirit is truly present. In a desperate act of faith, Drizzt sheathes his scimitars and stands defenseless. Zaknafein's swords tremble but do not strike. The true Zaknafein seizes control, warns Drizzt that Malice will never stop hunting him, and hurls himself into the acid lake, destroying the spirit-wraith forever.
In Menzoberranzan, Malice is shattered. Briza strikes her with a whip, an attack that confirms Lolth's abandonment, and kills her. House Baenre attacks from within; Matron Baenre had previously sent 200 soldiers to garrison House Do'Urden under the guise of protecting the vulnerable house from rivals, and these troops—secretly Jarlaxle's Bregan D'aerthe operatives—prove to be the true attackers. Jarlaxle offers Dinin a choice between joining Bregan D'aerthe or death. Dinin accepts, and House Do'Urden ceases to exist.
Drizzt mourns over the acid lake, telling Belwar that Zaknafein was present all along because spirit cannot be truly separated from the body. They retrieve Clacker's body; death has reversed the polymorph, revealing the pech's true, peaceful form. Returning to Blingdenstone, Drizzt decides to leave the Underdark entirely for the surface, reasoning that drow enmity will follow him through any underground tunnel. Belwar offers to accompany him, but Drizzt refuses, insisting the surface is no place for a svirfneblin. After 33 days of travel, Drizzt and Guenhwyvar emerge from a cave high on a mountainside into the night sky. Stars twinkle through broken clouds, the wind howls, and Drizzt stands still for a long time, watching the sky, with Guenhwyvar at his side.