A century after the end of the bloody war between the dwarves of Mithral Hall and the orc hordes of the orc king Obould Many-Arrows, the drow ranger Drizzt Do'Urden still wielded his magical scimitars, Twinkle and Icingdeath, as well as Taulmaril, the enchanted bow once possessed by his beloved wife, the human woman Catti-brie. Drizzt defeated a small group of bandits who were members of the vigilante organization called Casin Cu Calas, which traveled through the Kingdom of Many-Arrows and slew orcs in their sleep. Drizzt was assisted in the fight by Hralien, the leader of the elves of the Glimmerwood (formerly the Moonwood), and a few of his warriors. Drizzt was angered when one of the captives mentioned the so-called past weakness of Bruenor Battlehammer, the renowned former king of Mithral Hall, by making peace with the orcs. Reflecting on the hundred years of chaos that had gripped much of the world outside of the Silver Marches, Drizzt and Hralien discussed the momentous decisions made by Bruenor and Obould a century earlier and the impact that they had on the region. Also at that time, Obould VI, the sixth ruler of the Kingdom of Many-Arrows, reflected on the century of slow progress in the orc relations with the other races of the Silver Marches after he visited the home of an orc maiden who was set to marry a human from the Glimmerwood.
A century before these events, in 1372 DR, Drizzt and his traveling companion, the elf warrior Innovindil of the Moonwood, returned to Mithral Hall after a journey to the grave of the young elf Ellifain Tuuserail. By that time, Obould and his forces had completely blocked off the valley of Keeper’s Dale to prevent any counterattack from the dwarves of Mithral Hall and had begun building the first settlements of his new kingdom. A few of the orc priests who had pledged allegiance to Obould had become dissatisfied with the seeming end of the campaign against the Silver Marches and started conspiring against the king. In the hope of continuing the war, the shamans convinced Clan Karuck, a tribe of ogrillons (offspring of ogres and orcs) led by the chieftain Grguch, to leave their home in the Underdark and come to the surface of Toril.
Grguch and his followers soon began a campaign against the elves of the Moonwood, who had been highly successful at attacking the orc settlements along their borders. During a failed raid on an orc camp, the elves were surprised by the ferocity of Clan Karuck’s counterattack, but Tos'un Armgo, a renegade drow warrior and one of the original instigators of the orcs’ war against Mithral Hall, had been living alone in the area and led them to safety, a very uncharacteristic action for a dark elf. A short time later, Innovindil and a band of her brethren were assailed by Clan Karuck and their orc allies in the Moonwood itself, and the elves were once again routed. Clan Karuck’s cunning attack proved much more effective than their previous one, with Innovindil and her pegasus Sunset as well as twelve other elves being slain. Hralien suspected that Tos'un had planned the ambush because it was too well organized to have been thought of by orcs. However, the actual orchestrator was the gnome wizard Jack, who had been trained by illithids and other powerful creatures and had been secretly controlling Clan Karuck’s different shamans for centuries.
Meanwhile, in Mithral Hall, Bruenor was convinced that a sinkhole that the halfling Regis had fallen into in the Fell Pass months earlier was the way to the ancient dwarven homeland of Gauntlgrym, and he organized a small party to investigate. The skilled group consisted of Bruenor, Drizzt, Regis, the dwarf cleric Cordio Muffinhead, and the dwarf warriors Thibbledorf Pwent and Torgar Hammerstriker. After the friends left Mithral Hall and journeyed north through lands that were still gripped by winter, they entered the sinkhole only to find a cavern that was occupied by giant ethereal marauders. Once they killed the creatures, the group traveled deeper into the cavern and discovered a large underground city. However, upon exploring the city, which consisted of buildings that looked like ones found above ground and not under it, Drizzt and the others doubted that it was actually Gauntlgrym. The companions were then attacked by a nightwing and a nightwalker, two denizens of the Plane of Shadow, but together they managed to slay the fearsome entities. Following the fight, they entered a massive building and found extraordinary statues and tapestries of orcs and dwarves dwelling together in peace. A frustrated Bruenor and his comrades gathered as many scrolls as possible and brought them to Mithral Hall to Nanfoodle, a gnome alchemist and illusionist.
While Bruenor and the others had attempted to discover Gauntlgrym, Catti-brie and the barbarian warrior Wulfgar had departed from Mithral Hall in the early spring to search for the latter’s missing adopted daughter, Colson. Although Catti-brie had a seriously injured leg, she and Wulfgar traveled on foot to the city of Silverymoon, where she developed a closer relationship with its ruler, the wizard Alustriel Silverhand. Wulfgar and Catti-brie learned that Colson had probably been taken to the town of Nesmé, which had been destroyed by the trolls of the Evermoors a couple years earlier. When they reached Nesmé, the two companions discovered that the town was completely rebuilt and was much more fortified than it had been before the war against the trolls. Since Galen Firth, the captain of the Riders of Nesmé, was in command of the town, Wulfgar met with him in order to demand that Colson be given over to him. Despite having absolutely no liking for Wulfgar, Firth decided that it would be politically wise for him to acquiesce. With Colson retrieved, Wulfgar told Catti-brie that he had decided to take the young girl back to her birthmother and that he was going to return home to Icewind Dale to rejoin the Tribe of the Elk. Catti-brie was the only one of their group of friends who had not yet realized Wulfgar’s plans, and though she was saddened by them, she did not stop him from leaving. After returning Colson to her original home in the village of Auckney, Wulfgar began the long journey north to Icewind Dale.
In response to the attack on the Moonwood, Hralien made his way to Mithral Hall to ask for Drizzt’s help in tracking Tos'un, whom the elves believed was once again aiding the orcs. Once he learned that Innovindil was dead and that Tos'un wielded Khazid'hea, a powerful and sentient sword previously possessed by Catti-brie, Drizzt agreed to hunt down the rogue drow. The same day that Drizzt departed from Mithral Hall to begin his search for Tos'un, Catti-brie arrived at the dwarven stronghold with Alustriel and an entourage of Silverymoon wizards. The group from Silverymoon had traveled to Mithral Hall to help construct a new bridge across the River Surbrin, so that the dwarves would once again have efficient access to the rest of the Silver Marches and trade could be renewed. However, Bruenor was angry that Alustriel would not agree to rally the armies of the Silver Marches against the orcs, and he was determined to show that the scrolls recovered from the underground city told of how the orcs had betrayed the dwarves.
After the successful attacks against the elves, Clan Karuck and Toogwik Tuk, one of the orc priests who had conspired against Obould, raised an army numbering in the thousands from along the eastern edge of the Kingdom of Many-Arrows. Grguch led the horde in a direct attack against the not-quite-finished defensive wall that protected Mithral Hall’s eastern entrance. Since Alustriel’s wizards had prepared spells intended for the construction of the bridge across the River Surbrin, they were not prepared to help the dwarves resist Grguch’s forces when they launched an assault that night. The defenders were forced to retreat before the orcs’ onslaught, though not before Catti-brie had her first experience wielding the power of magic by using some powerful items given to her by Alustriel. By the time that the mages had prepared their battle spells and a dwarven force emerged from Mithral Hall the next morning, Grguch’s horde was gone and the entire building site was devastated. After collecting the bodies of the dead, Alustriel and her surviving wizards agreed to remain in the area to help rebuild the wall and finish the bridge, but she still would not send the armies of Silverymoon against the orcs, much to Bruenor’s rage.
Several days later, Nanfoodle and Regis deciphered the scrolls from the underground city, which were written in a language that was a mixture of dwarven and orcish alphabets. According to the text, dwarves and orcs had lived together for centuries in the city and relations had continued to improve between the two races. After gathering additional information from Regis, Nanfoodle ascertained that the only reason that the city fell was because something melted the permafrost beneath it, sucking the entire community and its population underground. Even after Regis and Nanfoodle revealed this information to Bruenor, the dwarf king was still determined to continue the war against the orcs. In his anger, Bruenor decided that the best way to defeat the enemy would be to lead a small but formidable group into the orc kingdom to assassinate Obould himself. Shortly afterward, a party consisting of Bruenor, Regis, Hralien, Torgar, Pwent, Cordio, and the dwarf fighter Shingles McRuff left Mithral Hall to find Drizzt and add his strength to their band before trying to kill Obould.
Once he was tracked down by Drizzt, Tos'un gave in to the urgings of Khazid'hea and attempted to kill the ranger, but after a ferocious fight he was subdued and disarmed. Tos'un claimed to be innocent of aiding the orcs in the new attacks, and he and Drizzt joined Bruenor and the others in the assassination mission. However, the companions were less than convinced of Tos'un’s innocence and decided to keep a watchful eye on him.
With all of Clan Karuck’s victories against both the elves and the dwarves, Grguch had made Obould’s armies restless and eager for war. In response, Obould sent the orc shaman Nukkels to parley with the dwarves and apologize for the attacks, and he also dispatched a messenger to Grguch. The riders sent to Mithral Hall were captured by treacherous orcs, and when Grguch learned of the peace mission, he killed the messenger sent to him by Obould and prepared his own forces for an assault on Obould’s encampment in order to overthrow the king and continue the war against the Silver Marches. As Bruenor and his companions traveled toward Obould’s camp, Drizzt and Hralien searched for a way to prove Tos'un’s blamelessness in the new orc offensive. Overhearing a discussion between two of the original orc conspirators that proved Tos'un’s innocence, Drizzt confirmed that the rogue drow could be trusted, and the group immediately moved to confront Obould.
Upon their arrival, Drizzt and his companions discovered a brutal battle raging between the followers of Obould and Grguch, and the orc leaders themselves engaged in single combat. Obould was slowly gaining the advantage in the fight until Hakuun, the ogrillon shaman of Clan Karuck who was being by possessed by Jack, started blasting the orc king with lightning bolts. As Drizzt and his comrades fought their way through the battling forces toward the orc leaders, the drow ranger forced Bruenor to choose the fate of the region: war or peace with the orcs. Bruenor made his decision by leaping atop the weakened Obould to launch himself at Grguch. While his other friends continued to battle the orc soldiers, Drizzt engaged Hakuun and ultimately slew the shaman as well as the shape-shifting Jack. Bruenor fought a vicious duel against Grguch, which ended with the ogrillon chieftain disemboweled and decapitated after Obould joined the clash.
Once Grguch’s remaining followers were defeated, a battered Bruenor and Regis, who had been seriously wounded in the fighting, were brought before Obould. As Bruenor and Obould stared each other down, Nukkels healed Regis at the orc king’s command. Obould then lowered his weapon and agreed to establish peace with Mithral Hall and the other nations of the Silver Marches. Due to Tos'un’s brave actions during the battle, Hralien decided to allow him to live alongside the elves in the Moonwood.
When Bruenor and his companions returned from the fateful battle, Drizzt gave Catti-brie the enchanted robes that he had taken from Jack’s corpse, and she began to be tutored in the magical arts by Alustriel and Nanfoodle. A short time later, in the large chamber in Mithral Hall known as Garumn’s Gorge, Bruenor and Obould signed a treaty that ended the war between the two peoples and officially established the Kingdom of Many-Arrows.
A century after the signing of the Treaty of Garumn’s Gorge, Drizzt and Hralien remained with the captured members of Casin Cu Calas while they reflected on those past events. The two discussed how Bruenor’s brave decision to accept peace with Obould had been for the greater good and had brought a century of relative peace to the Silver Marches. Drizzt also mentioned how Hralien’s trust in Tos'un all those years earlier had resulted in the drow marrying the elf leader Sinnifain and the couple having two children together.