Following the Eternal Empire conquest that toppled the Galactic Republic and the Sith Empire, the Wild Space shadowport of Asylum became a sanctuary for refugees fleeing the tyranny of the Eternal Empire on Zakuul. Among the refugees were the Scions of Zakuul and their leader Heskal, who had fled the Scion massacre instituted by Eternal Emperor Arcann. Following the rescue of the Outlander from Zakuul in 3631 BBY, former Zakuulan officer Koth Vortena and his compatriots - Sith Lord Lana Beniko, renegade Knight of Zakuul Senya Tirall, and the bodyguard droid HK-55 - fled Zakuul onboard the Gravestone, an ancient combat frigate that had been able to fight against the Eternal Fleet, and docked at Asylum for repairs. There they picked up Vortena's crew, which included Len Parvek, Ralo and Tora to restore the ship to full working condition. While the ship underwent repairs, the Outlander and Senya Tirall made an excursion to Zakuul, returning with Beniko's astromech droid T7-O1 and advanced artificial intelligence calling herself SCORPIO. Meanwhile, Heskal expirienced a vision of Arcann's defeat at the hand of the Outlander and acting in accordance with his prophecy, contacted the Emperor he detested and invited him to Asylum.
Arcann made his way to Asylum before his Eternal Fleet did and personally executed the Scions in their hideout, impaling Heskal on his lightsaber just as the Outlander arrived to meet with him. Arcann then offered the Outlander to peacefully return to carbonite and surrender the Gravestone, promising that their crew could leave freely. However, Valkorion warned the Outlander that Arcann would betray them and a fight between the two ensued. The Eternal Fleet emerged from hyperspace and opened fire on the shadowport, while the shuttles began deploying Skytroopers and Knights of Zakuul. Civilian vessels filled with refugees attempted to flee, but many were shot down by the Eternal Fleet, while Asylum's local criminal elements such as Tanno Vik's Blast Crew joined fighting against the invaders. The Gravestone remained docked, but SCORPIO upgraded its targeting algorithms, using the turbolaser to shoot down several shuttles, one of which crashed into the Scions' hideout, interrupting Arcann's fight with the Outlander.
The Outlander and T7-O1 rushed back to the Gravestone, encountering and defeating Knight-Captain Dasch Nilrann, before witnessing Heskal expiring from his wounds. Arcann's forced took over the the Control Spar, taking control of blast doors, turbolifts and docking clamps, keeping the Gravestone grounded. Koth Vortena and HK-55 went to the Control Spar, while their crew stayed behind to defend the Gravestone. Their position was threatened by a group of Knights led by High Justice Vaylin herself, who almost threw Vortena's crew members off the platform's edge. Vaylin was about to engage the Outlander and Lana Beniko when her mother Senya Tirall rushed to aid the defenders. She dispatched a Zakuulan Knight going after Koth's crew before telekinetically tossing the Outlander away before Vaylin could land a blow. Senya then urged Beniko to follow the Outlander and free the Gravestone, while she stayed behind to deal with her daughter, and the two engaged in a lightsaber duel. The Outlander and Beniko soon reached Vortena's position, where Beniko volunteered to hold a choke point so that Vortena and the Outlander could reach the Control Spar.
Vortena and the Outlander dispatched an Eternal Empire Walker before boarding the shuttle that Vortena piloted to the Control Spar, where they rejoined HK-55. After killing Knight-Captain Lazna Delothrea, Vortena and the droid stayed behind to hold off a battalion of Zakuul Knights using tripwire ambushes. The Outlander proceeded to the Control Spar and released the docking clamps keeping the Gravestone in place, but was once again confronted by Arcann. HK-55 arrived just in time to assist the Outlander during a battle, sacrificing himself to shield his master from Arcann's Force blast. With Arcann being too strong for the Outlander, Valkorion offered to share his power, but was refused and the Outlander was stabbed by Arcann's lightsaber. Their companion then arrived and used their surroundings to knock Arcann off the Control Spar to the levels down below, before escorting the injured Outlander back to the Gravestone by the shuttle. Meanwhile, Senya managed to disarm Vaylin and had her daughter at her mercy, she could not bring herself to land a finishing strike. Everyone got back to the Gravestone just as the vessel was taking off. Vortena took the ship towards the Eternal Fleet blockade, where despite the omnicannon being offline, he still managed to destroy one Eternal Fleet warship with the turbolasers. Just as the Eternal Fleet prepared to open concentrated fire, the Gravestone jumped into hyperspace.
As soon as they were safe, the Outlander collapsed from sustained injuries and spent several days recovering. Meanwhile, Arcann survived his fall and informed Vaylin that Valkorion's power had diminished. No longer facing any resistance, the Eternal Empire forces completely leveled Asylum. However, the battle also showed the galaxy that Zakuul was not invincible and Beniko's contacts in the Galactic Republic and the Sith Empire threw their support behind the Outlander, gathering on Odessen and starting an Alliance dedicated to bringing down the Eternal Throne. HK-55 was destroyed seemingly beyond repair and did not possess a backup memory core to graft into another droid body, however his chassis were later recovered by Doctor Juvard Illip Oggurobb, who eventually managed to reconstruct the droid with some modifications, although without his old memory core the droid did not recall any previous interactions with the Outlander.
Tanno Vik and the Blast Crew only join the fight if the player had previously spared him during Chapter VIII: Asylum. During the second duel against Arcann, Valkorion will offer the player to use his power to defeat his son. If the player refuses for Light Side points, Arcann impales the player with his lightsaber, but is knocked off the platform by either Koth Vortena or Lana Beniko, depending on who has higher affection with the player. If the player accepts Valkorion's offer for Dark Side points, they will unleash a a storm of Force lightning, which Arcann barely managed to hold against before being similarly knocked off; the storm also engulfs several refugee starships in proximity of the Control Spar, instantly killing thousands aboard. Finally, if the player declines the offer after accepting Valkorion's power on two previous occasios, Valkorion will overrule the player's decision and unleash the storm regardless.