The eighteenth episode of the Star Wars: The Clone Wars animated series, "The Citadel," constitutes the third season's offering. Its original broadcast date was February 18, 2011.
"An elite squad comprised of Jedi Knights and clone troopers, spearheaded by Obi-Wan and Anakin, endeavors to rescue the captive Jedi General Even Piell from a supposedly impenetrable prison, aided by R2-D2 and a group of reprogrammed battle droids. Despite explicit instructions to remain behind, Ahsoka Tano secretly joins the mission, proving invaluable as the infiltration unfolds. Piell, along with his fleet officer Captain Tarkin, are successfully extracted from their confinement, but now the escapees must navigate their way out of the Citadel itself."
At the Jedi Temple located on Coruscant, Master Plo Koon briefs Obi-Wan Kenobi and Anakin Skywalker, along with their assembled team—including Commander Cody, Captain Rex, and the recently promoted ARC troopers Echo and Fives—regarding their latest mission: to penetrate the "impenetrable" fortress known as the Citadel, situated on the Separatist world of Lola Sayu. Their objective is the extraction of Master Even Piell before the Separatist forces compel him to divulge the coordinates of the Nexus Route. Regrettably, the data concerning the Citadel obtained from the Jedi Archives is outdated, and acquiring fresh intelligence has proven impossible due to the Citadel's design specifically for detaining high-profile prisoners, particularly Jedi.
The scheme involves a strategy conceived by Anakin, utilizing reprogrammed battle droids under the command of R2-D2 to pilot a Class type B escort shuttle through the defense perimeter in orbit. The human and clone members of the team are to be encased in carbonite to deceive life-form detection systems. However, Anakin's apprentice, Ahsoka Tano, expresses discontent at being excluded, as her master believes the mission is too perilous for her. Even her appeal to her acquaintance Master Koon provides minimal solace.
Following the strike team's carbon-freezing by Erk Zallis, they are loaded onto the shuttle for transport to the Citadel. Upon the droid vessel's arrival in orbit above Lola Sayu, the Citadel's warden, Osi Sobeck, and his tactical droid, K2-B4, scrutinize the cargo. The ship and its contents successfully clear the scans and proceed to land within a cavern adjacent to the Citadel, where the droids offload and thaw the strike team. Much to their surprise, Anakin and Obi-Wan discover that Ahsoka has secretly frozen herself and stowed away with the group, asserting that she is acting under Master Koon's orders. Unable to send her back, they decide to allow her to participate.
The initial obstacle manifests as a cliff face exposed to intense winds and strewn with electromines, rendering jetpacks and grappling cables unusable. The cliff represents the only path to a concealed side entrance, which is both regularly patrolled and fortified by a ray shield. Ahsoka demonstrates her value to the team by successfully infiltrating the facility through a ventilation shaft and disabling the shield from within. However, during the team's ascent, clone trooper Charger loses his footing, plummeting down the cliff and triggering a mine, thereby alerting Sobeck to the Jedi's infiltration of the Citadel, initiating an alarm.
As the team progresses through the corridors, they encounter numerous traps, including laser guns mounted on the walls and a moving electrified barrier that results in the demise of another clone trooper. They manage to locate and rescue Master Piell before a droid interrogator can torture him. Nevertheless, the Jedi discover that, although Master Piell erased the Nexus coordinates from his ship's databases, he committed them to memory in two parts, entrusting the other half to his captain. With both officers held in separate cells within the Citadel, Piell was forced to surrender his portion of the code, thus requiring the liberation of the fleet captain to safeguard the Nexus Route.
Subsequently, Anakin, Ahsoka, Obi-Wan, Piell, and the remaining team members proceed toward the other cells, only to be ambushed by commando droids. Sobeck activates a magnetic ceiling, which disarms the team and restrains Anakin by his prosthetic hand. Obi-Wan, Piell, and Ahsoka attempt to subdue the commando droids using the Force, but the droids are equipped with magnetized foot plates, merely keeping them off-balance. Despite Sobeck's attempt to incapacitate him with electricity, Anakin manages to reach his lightsaber and deactivate the magnets, enabling the others to recover their weapons.
The Jedi and their team then locate Piell's officer, Captain Wilhuff Tarkin, along with the other officers. Obi-Wan and Anakin decide to divide the team, with Obi-Wan, Cody, and Piell creating a diversion while Anakin, Ahsoka, Rex, Echo, and Fives escort Tarkin to safety. Tarkin advocates for maintaining a unified team to maximize their numbers, but Master Piell concurs with Kenobi's strategy, and Obi-Wan's team departs. Anakin breaches a wall, revealing a cavern system that was included in the limited information from the Jedi archives. Despite Tarkin's skepticism and vocal criticism, Anakin remains determined to proceed.
The carbon freezing strategy had been previously utilized in the Clone Wars graphic novella title The Clone Wars: Shipyards of Doom. However, due to Skywalker's remark that this is "the first time" this approach has been used in this episode, a continuity discrepancy arises, as the events of Shipyards occurred prior to the episode. This contradiction was resolved when the graphic novella was reclassified into the Legends continuity in 2014.
During Ahsoka's request to speak with Master Plo in the hangar before the strike team's departure, a shot from behind reveals that her Padawan braid is absent.