"Lightsaber Lost" marks the eleventh installment of Star Wars: The Clone Wars television show's second season. Following a two-week break in the series' broadcast schedule, it was broadcast on January 22, 2010.
Anakin and Ahsoka find themselves in the underbelly of Coruscant, hunting for Car Affa, a dealer in arms who is providing Republic weaponry to the Separatists. Upon reaching a tavern that serves as Affa's hideout, Anakin tells Ahsoka to remain outside as he moves in to capture the wanted man. As the tavern's occupants rush out, Ahsoka is knocked off balance by the throng. Noticing that her lightsaber has vanished, she spots it briefly in the grasp of a pickpocket. She gives chase, but the thief disappears into the crowd. Choosing not to tell Anakin about her mishap, she makes her way to the Archives inside the Jedi Temple, hoping that Jocasta Nu can offer some help in finding the culprit. Jocasta Nu is not helpful due to her limited knowledge of Coruscant’s criminal element, but luckily she is able to direct her towards the one person who can help: Tera Sinube, a Jedi Master who possesses specialized knowledge of Coruscant's criminal world. Sinube identifies Ahsoka's thief in the database as a Patrolian named Bannamu. Despite Ahsoka's eagerness to leave, Sinube insists on joining her, suggesting that a more measured approach will aid in her search.
Returning to the slum area, they receive directions to Bannamu's secret location—the Spider Arms Hostel. Ahsoka eventually tracks down Bannamu and discovers that he has already sold her lightsaber to an assassin known as Nack Movers. The two Jedi quickly set out to find him, with Sinube once again urging Ahsoka to practice patience. Arriving at the apartment of Movers' girlfriend, they find the door forced open and Movers dead. Soon after, the Jedi encounter a frightened woman named Ione Marcy hiding in the apartment, who wants to know if Movers' killers have left. Ahsoka proceeds to search the bedroom, where she is ambushed by Cassie Cryar, who is wielding Ahsoka's lightsaber. Upon learning that Ahsoka is a Jedi (but not knowing she is only a Padawan), Cassie leaps out the window and flees across the city's rooftops. Ahsoka pursues her and informs Sinube of the situation.
Sinube notices a contradiction because Ahsoka's attacker was a female while Ione Marcy claims that men had broken into the apartment. Along with sensing something more than just shock in her, Sinube concludes that Ione Marcy was involved in the crime. He discreetly plants a tracking device on her and calls for GU-series Guardian police droids, but Ione manages to escape in an airspeeder.
In the meantime, Ahsoka is gaining ground on Cassie atop a tall building, when Cassie jumps and lands in Ione's passing speeder. Sinube picks up Ahsoka in another speeder, and they track the device to a train station. Police droids capture Ione, but Cassie manages to escape onto the roof of a departing train. Ahsoka gives chase and they end up inside a train car, where Cassie seizes a Twi'lek mother and her child as hostages, still holding Ahsoka's lightsaber. As the train pulls into the next station, Cassie tries to flee again, but Sinube, who arrived earlier, stops her and takes the lightsaber. Cassie is then taken into custody. Later, Sinube advises Ahsoka to share the lesson she has learned as they head to the Jedi Temple. Master Yoda greets them and invites Ahsoka to share with the younglings the value of patience and the responsibilities of never losing their lightsabers.
The flashback featured in this episode includes a scene taken from the first season finale titled, "Hostage Crisis." Despite airing before, the official timeline dictates that those events transpire after those depicted in "Lightsaber Lost."
When Ahsoka visits Jocasta Nu in the Jedi Archives Library, a criminal file on Brea Tonnika is visible on the computer Nu is using. The Aurebesh text next to her picture reads "LAST SEEN ON CORUSCANT WANTED FOR MURDER."
While Ahsoka is searching for a lightsaber to purchase near the noodle stand, the word "Massage" is written on the wall behind her.
During the scene where Ahsoka and Master Sinube are walking down the hall toward Nack Movers' apartment, Ahsoka's sash can be seen passing through the bottom of her skirt.
During Ahsoka's pursuit of Cassie Cryar, numerous floating advertising boards they jump over feature Aurebesh writing. One such board reads "SODA," another reads "STAR TOURS GLEE ANSELM CALL 1-800-555-6576 NOW!" The text under Palpatine reads "KUAT DRIVE YARDS AWARD" before being cut off.
Despite one of the floating ads Ahsoka jumps on featuring Palpatine making a speech, and that the speech is included in the quotes on the episode guide, neither the character nor Ian Abercrombie, the Supreme Chancellor's usual voice actor, appear in the credits.
A list of destinations that appears at the hovertrain station includes Burbank, a reference and in-joke to the town in California. A similar in-joke would appear later in the Season 5 episode, "To Catch a Jedi."
Pablo Hidalgo has stated that Cassie Cryar and Ione Marcy were originally intended to be lovers.
This episode draws inspiration from the classic 1949 film Stray Dog by Akira Kurosawa, which centers on a rookie Japanese police detective trying to recover his stolen pistol with the help of an experienced investigator.
The episode's conclusion features two partially visible stained glass windows depicting Valenthyne Farfalla leading the Army of Light, and Farfalla and Lord Hoth from the comic book series Star Wars: Jedi vs. Sith.