During the Clone Wars, the Galactic Republic mounted a mission to capture a strategic Separatist supply storage base. The Republic and Jedi Order had received intelligence that the asteroid contained medications, weapons, ship repair materials, and foodstuffs which would be vital to worlds in desperate need. A joint Jedi and Republic force went to capture these supplies. However, the facility and all of its supplies were destroyed thanks to the efforts of Jedi Master Quinlan Vos, who was secretly serving as an agent of Count Dooku.
Quinlan Vos (pictured) worked as a double agent for Count Dooku as part of his own plan to destroy the Sith.
Towards the end of the Clone Wars, the Jedi Order received a tip about the location of a Separatist supply storage base. The base was massive and concealed within the interior of a asteroid. According to the source, the asteroid contained medications, weapons, ship repair parts, and foodstuffs which were of vital help to worlds in desperate need. Upon learning of this storage base, the Jedi High Council hatched a mission to seize the base and distribute the supplies to needy worlds. By seizing these supplies, the Jedi also planned to deny them to the Confederacy of Independent Systems.
Jedi Master Mace Windu placed Masters Obi-Wan Kenobi and Quinlan Vos in charge of the mission. He also instructed the two masters to bring two other Jedi with them and enough clone troopers to transport the supplies. For this mission, Kenobi picked his former Padawan Anakin Skywalker and another Jedi Knight named Akar-Deshu, who was a friend of Vos. Unknown to the Jedi and Galactic Republic, Vos had turned to the dark side of the Force and was Count Dooku's secret apprentice. Secretly, Vos had joined forces with Dooku in order to learn the identity of his secret Sith master Darth Sidious and destroy both Sith Lords. To gain Dooku's trust, he supplied the Separatists with intelligence about the planned Jedi and Republic operation.
Expecting resistance from Separatist starfighters, Kenobi, Anakin, Vos, and Desh flew to the asteroid base in their Eta-2 Actis-class interceptors. Sure enough, six vulture droids emerged from the asteroid base to engage them. The Jedi starfighters quickly eliminated the droid fighters and managed to penetrate the tunnel leading to the base. There, the found a large stockpile of supplies.
While Anakin, Kenobi, and Vos landed their starfighters, Desh returned in his Jedi starfighter to their Arquitens-class light cruiser to tell the clone troopers to bring transports. Before the Jedi could begin exploring or surveying the cavern, the Clone Commander Cody arrived with three transports. Before the Jedi and clones could begin loading the supplies, Vos discovered that the Separatists had rigged the entire asteroid to blow up. There was no chance of disarming them because there were at least six bombs and they all had been timed to explode in three minutes.
Unable to disarm the bombs, the Jedi and clones were forced to abandon the asteroid storage base. They managed to escape minutes before an explosion ripped through the asteroid, destroying most of the supplies. Following the explosion, Master Kenobi instructed Desh to keep a single transport in the vicinity to search for any salvageable debris. Since the explosion had failed to shatter the asteroid. Kenobi thought that there would be some salvageable supplies there. While Desh stayed behind to salvage supplies, Kenobi, Skywalker, and Vos returned to Coruscant to inform the Council of the failed mission.
To reward Master Vos for saving many lives on the failed asteroid salvage mission, the Jedi Council assigned him to lead an attack on a Separatist listening post on the planet Vanqor. However, Vos informed Count Dooku about the planned Jedi and Republic operation. As a result, the Separatists were able to evacuate the facility before the arrival of the Jedi and clone troopers. Suspecting that this incident was no coincidence, Vos' Jedi colleagues and the Council came to suspect that they had a traitor was leaking information to the Separatists.
Their suspicions of treason were confirmed when Desh uncovered evidence among the asteroid debris that the bombs were Republic-issue weapons. As a result, the Jedi deduced that there was a traitor within their ranks. While Windu suspected that Vos had planted those bombs, Kenobi urged for caution until they had enough evidence to either prove or disprove Vos' treason. Agreeing with Kenobi, Yoda decided to talk with Vos in private. After Yoda discerned that Vos had indeed fallen to the dark side, the Council sent him on a mission to kill Count Dooku in order to test his loyalty to the Jedi and Republic. This led to the events of the second battle of Christophsis.