During the Clone Wars era, the Jedi Order launched an operation with the objective of rescuing Jedi Master Quinlan Vos. He had been captured while he was on a secret assignment to assassinate Count Dooku.
Following Asajj Ventress's unsuccessful endeavor to save Quinlan Vos and turn him away from the dark side on Serenno, she made her escape and subsequently encountered Jedi Master Obi-Wan Kenobi at a cantina on Coruscant. Approximately a month later, Ventress crossed paths with the Mahran Jedi Knight Akar-Deshu. Despite her initial reluctance and resistance to conversation, he informed her that Kenobi had shared the details of Vos's situation with the Jedi High Council. Subsequently, he brought her before the Jedi Council, accompanying her to the Jedi Council Chamber.
Upon Ventress's arrival in the chamber, Mace Windu presented her with an arrest warrant. However, Masters Kenobi and Yoda offered her an opportunity to provide information regarding Quinlan Vos. As she began to explain, the Council members, particularly Mace Windu, subjected her to interrogation filled with suspicion and animosity. Ventress responded truthfully, admitting that she had trained Quinlan Vos in the ways of the dark side, believing it to be the most effective approach to strengthening them for the purpose of assassinating Dooku. This revelation deeply shocked the Council members. Nevertheless, Ventress emphasized that it was the Jedi Council themselves who had desired her and Quinlan Vos to partner up in order to assassinate Dooku.
After she, Desh, and Anakin Skywalker departed from the Council Chambers, the Council engaged in a discussion regarding this new information. Kenobi expressed his belief that there remained a possibility of rescuing Vos from the dark side, although this sentiment was met with varied reactions from the Council members. Suddenly, Admiral Wullf Yularen contacted the Jedi Council, providing intelligence concerning Count Dooku and his mysterious "Admiral Enigma." Specifically, it was reported that Dooku's Providence-class Dreadnought had been observed above the planet of Taris, poised to launch an attack. Subsequently, Yoda presented Ventress with an offer: if she assisted Kenobi and Skywalker in bringing Vos back to the Jedi Temple, she would receive a full pardon for her war crimes.
Skywalker, Kenobi, and Ventress boarded the vessel known as the Banshee, with Ventress piloting it into the hangar of Dooku's capital ship, which was leading the fleet. The bounty hunter utilized Separatist codes to deactivate the hangar shields, granting them access. Upon a safe landing, they concluded that this "Admiral Enigma"—Vos—was located on the bridge of the destroyer.
Ventress guided the two Jedi through the corridors of the destroyer, carefully avoiding patrols of battle droid. Upon reaching the bridge, the figure who emerged from the captain's chair was not Vos, but rather Dooku himself. With his red blade ignited, Anakin promptly engaged Dooku, leaping towards him with his own blue lightsaber.
As Skywalker and Dooku engaged in a duel, the numerous battle droids present on the bridge opened fire on Ventress and Kenobi. While Ventress accessed the computer located on the lowest level of the bridge, Kenobi provided cover by deflecting the incoming blaster fire with his own lightsaber. Ventress also employed the Force to throw two battle droids together, creating a distraction for Dooku. Seizing the opportunity, Dooku retreated to the second level, with Skywalker closely pursuing him.
The duel between Anakin and Dooku appeared to be at a standstill. The Sith Lord unleashed a burst of blue Force lightning at his opponent. Skywalker raised his blade to shield himself from the lightning. Simultaneously, Dooku utilized the Force to hurl debris from a destroyed battle droid at Anakin. Anakin evaded the projectiles by leaping to the third level below, with Dooku continuing his pursuit.
Additional droids entered the bridge, initiating fire upon Ventress and Obi-Wan. While they were redirecting the blaster fire, Kenobi accessed the ship's computer and discovered that Quinlan Vos was being held imprisoned in the ship's brig located below. He also realized that the "Admiral Enigma" persona was a fabrication. He deduced that Dooku had been exploiting Vos to undermine Jedi morale. As Ventress and Kenobi fled the bridge towards the brig, Anakin continued his battle with Dooku.
Upon entering Vos's cell in the brig, Ventress and Kenobi discovered Vos in a weakened state, suspended from the ceiling by glowing shackles. To maintain the illusion that Vos was a prisoner, Dooku had subjected him to whipping. Vos appeared pleased to see both his former lover, Ventress, and his fellow Jedi Master, Kenobi. As the two freed Vos from his restraints, Ventress noticed a flicker in his eyes and realized that he had embraced the dark side of the Force. However, Kenobi dismissed Ventress's concerns, and Vos asserted that he remained loyal to the light side and Ventress.
Asajj attempted to strike down Vos with her lightsaber, but Kenobi intervened and restrained her. Before a confrontation could escalate, battle droids arrived in the brig, forcing the trio to flee. Shortly thereafter, they were reunited with Skywalker, who utilized his lightsaber to cut a circular hole through the ceiling, crushing the battle droids below. After returning to the hangar, the four boarded Ventress's ship, the Banshee, and escaped into space. While Kenobi and Skywalker were relieved to have rescued Vos, Ventress remained convinced that Vos could not be trusted. After evading vulture droids, the four escaped on the Banshee into hyperspace.
Despite the successful rescue of Quinlan Vos, the Jedi mission inadvertently served the interests of the Separatists. During his captivity under Dooku, Vos had already succumbed to the dark side and become the Sith Lord's apprentice. Secretly, Vos intended to exploit his apprenticeship under Dooku to compel the Sith Lord to lead him to Darth Sidious, thereby enabling him to destroy the Sith. Leveraging his position within the Jedi Order, Vos leaked confidential information regarding at least two Republic military operations to the Separatists. After Yoda confirmed that Vos had indeed embraced the dark side, the Jedi Council devised a mission for Vos to assassinate Dooku. Failure to pass this test would result in his arrest for treason. Meanwhile, Vos managed to reconcile with Ventress and reaffirmed his commitment to marry her once he had eliminated Dooku.
As anticipated, Vos failed in his mission, and he, along with Dooku, were promptly apprehended by Kenobi and Skywalker. However, Vos managed to break free from his restraints and release Dooku. During the escape attempt, he killed two of his Jedi colleagues, Akar-Deshu and Kav Bayons. Accompanied by Ventress, Vos and Dooku escaped aboard the Banshee and crash-landed on Christophsis. After making their way to the Separatist base located there, Dooku contacted Darth Sidious, seeking assistance in their extraction from the planet. Vos only caught a brief glimpse of the enigmatic Sith Lord. Shortly thereafter, the Jedi and Republic attacked the Separatist base.
During the ensuing battle, Ventress was seemingly killed when she absorbed the full force of Dooku's Force lightning in an effort to protect her lover, Vos. Dooku then attempted to provoke Vos into killing him, but the Jedi Master resisted the temptation and returned to the light side. While the Jedi secured the base and took Vos into custody, Dooku managed to escape with the assistance of Sidious. Given that the mission to assassinate Dooku had brought Vos perilously close to the dark side, the Jedi abandoned any future attempts to assassinate Dooku.