During the Galactic Civil War, specifically during the Yavin blockade, a mission was undertaken to the planet Fondor. It was during this operation that Luke Skywalker successfully obtained the plans for the Executor from the forces of the Empire. This mission marked the initial encounter between Luke Skywalker and Darth Vader.
Following the Battle of Yavin, Admiral Amise Griff served as an agent provocateur on the industrial world of Fondor for Supreme Commander Darth Vader, a role he executed with great effectiveness. This planet housed the Fondor Shipyards, the construction site of the Dark Lord's new flagship, the Super Star Destroyer Executor, which was nearing its completion. Griff managed to infiltrate a group of disloyal Imperial admirals involved in the building of the Executor, and he routinely reported their activities to Lord Vader. While the officers held no particular affection for the Rebel Alliance, they were becoming increasingly resentful of Vader's unique position within the Imperial naval hierarchy. By pretending to share their contempt for Vader and by aiding in the successful organization of their schemes, Griff eventually rose to become the leader of these conspirators.
As the blockade of Yavin 4 stretched on for longer than anticipated, the treacherous officers hatched a scheme to embarrass the Sith Lord by providing the Rebels with the schematics of Vader's new flagship, the Executor. To this end, they dispatched a drone craft to the Rebels under siege on Yavin 4, making them this offer. Despite Rebel suspicions of a trap, Luke Skywalker volunteered to undertake the mission to Fondor.
Subsequently, Luke Skywalker journeyed to Fondor aboard a civilian craft accompanied by the droids R2-D2 and C-3PO. Upon their arrival in the Fondor system, Skywalker was contacted by Admiral Griff, who continued to present himself as an ally of the Rebellion. The officer facilitated the young man's entry onto the planet and met with him on the surface. During their initial discussions, Griff skillfully misled Skywalker, convincing him that the Rebels could also sabotage the Executor before its completion. Recognizing the Rebel agent's identity, Admiral Griff devised a new strategy to ensnare the Rebel hero. His plan involved arranging a meeting between Skywalker and the conspirators, with the aim of directly implicating the treacherous officers and capturing the Rebel hero in the process. Vader approved of Griff's plan and decided to oversee the operation personally.
Luke Skywalker then convened with the Imperial officers within Fondor's underground steam tubes. As Vader deployed stormtroopers in the vicinity, Skywalker sensed his powerful dark presence through the Force. Consequently, the young man opted to call off the meeting, but the treacherous officers disregarded his warnings. When Imperial troops launched their attack, Skywalker managed to evade capture while all the conspirators were apprehended. Thanks to the assistance of Tanith Shire, a young Fondorian woman and Rebel sympathizer, who disoriented the stormtroopers by releasing steam into the tunnels, the young Rebel successfully escaped Fondor's underground steam tubes.
Ultimately, Luke Skywalker, R2-D2, C-3PO, and Tanith Shire departed the Fondor system aboard a stolen drone barge, carrying the Executor schematics with them. Admiral Griff's operation proved to be a complete failure, as Skywalker escaped with the plans. Conversely, Darth Vader was deeply disturbed after sensing his son's presence for the first time. The Sith Lord realized that Obi-Wan Kenobi might have trained a Jedi apprentice, a development that could pose a greater threat to the Empire than any other.
Despite its depiction on the cover of the 1992 reprint, Classic Star Wars 4, Luke Skywalker does not engage Darth Vader in a lightsaber duel.