The lightsaber duel that transpired on Cloud City, located on the planet Bespin, is famously known as the Duel on Cloud City. Following his failure to successfully capture Luke Skywalker during the Battle of Hoth, Darth Vader, who was actually Skywalker's father, devised a scheme to ensnare Skywalker on Bespin's Cloud City. In an attempt to lure Skywalker out of hiding, he took Han Solo and Leia Organa captive and subjected them to torture. While training with Jedi Master Yoda on Dagobah, Skywalker experienced a vision of his comrades' suffering and, despite the warnings of both Yoda and Obi-Wan Kenobi, he immediately traveled to Cloud City to offer assistance.
Upon his arrival, Skywalker briefly encountered Imperial forces and Boba Fett, who was in the process of transporting a carbon-frozen Solo to his ship. Successfully avoiding the enemy troops, Skywalker proceeded to the carbon-freezing chamber, where he found Vader awaiting him. The two engaged in a lightsaber duel that spanned the entirety of the chamber. The duel continued through the city's processing vane and onto a maintenance catwalk, where Vader severed Skywalker's weapon hand, thus disarming him. He then attempted to entice the young Jedi apprentice to join him and embrace the dark side. When Luke refused, Vader made the shocking revelation that he was, in fact, Anakin Skywalker, Luke's father.
Choosing to avoid capture, Skywalker leaped from the platform where they had been fighting, ultimately landing and hanging precariously at the city's lower levels. Organa, Chewbacca, and Lando Calrissian rescued Skywalker aboard the Millennium Falcon. They then returned to the Rebel fleet and began strategizing a mission to save Solo from Jabba the Hutt on Tatooine.
The Alliance to Restore the Republic had suffered a devastating defeat in the Battle of Hoth in the days leading up to the duel. While the Alliance managed to prevent complete annihilation, the battle resulted in the destruction of the Alliance's new headquarters and the scattering of its surviving forces. As the Imperial assault reached its conclusion, Han Solo, Leia Organa, Chewbacca, and C-3PO successfully escaped off-world in Solo's personal vessel, the Millennium Falcon. However, the Falcon had undergone extensive repairs prior to the battle, leaving its hyperdrive motivator severely damaged and non-functional. The leader of the Imperial assault was Darth Vader, who was actively seeking to locate and capture Luke Skywalker with the intention of making the boy, whom he knew was his son, his apprentice. He arrived at the hangar where the Falcon had been docked just as the ship was departing.

Recognizing the significance of Skywalker's friends to him, Vader determined that he could exploit them to draw the boy out. Vader believed that capturing and torturing Skywalker's friends would cause the young Jedi to sense their pain through the Force, prompting him to attempt a rescue. Consequently, he instructed his personal armada, Death Squadron, to intercept the Falcon as soon as it escaped Echo Base. Solo managed to evade his pursuers, but he soon realized that the damage to the Falcon's hyperdrive was so extensive that he could not repair it without assistance. Unable to rendezvous with the remaining Rebel fleet, Solo sought refuge on the nearby planet of Bespin, where an old acquaintance, Lando Calrissian, had become Baron Administrator of Cloud City, Bespin's largest settlement.
As the Falcon journeyed to Bespin, with Solo's belief that Calrissian could aid in repairing the Falcon, they were unknowingly tracked by the bounty hunter Boba Fett. Fett informed Darth Vader of Solo's destination, and, possessing functioning hyperdrives, an Imperial detachment under the Dark Lord's command arrived at Bespin before Solo's crew. Upon arriving at Cloud City, Vader informed Calrissian of his plan to use Solo and his friends to capture Skywalker. In exchange for his cooperation, Vader promised that the Empire would leave Cloud City undisturbed after Skywalker's capture. Faced with the looming threat of Imperial occupation, Calrissian reluctantly complied. With his cooperation, Vader captured Solo and his companions shortly after their arrival. He then began torturing the Rebels in an attempt to lure out Skywalker.

At that point, Skywalker had heeded the advice of Obi-Wan Kenobi's Force spirit and traveled to the planet Dagobah, where he continued his Jedi training under Grand Master Yoda for several weeks. Vader's plan proved successful; Skywalker sensed his friends' distress and prepared to travel to Bespin to rescue them. In doing so, he disregarded the advice and pleas of Yoda and Kenobi, the latter of whom warned Skywalker that his friends' suffering was almost certainly part of a trap. Luke approached Cloud City in his X-wing starfighter, unaware that the Imperial forces occupying the city had been monitoring his progress since his arrival in orbit. He landed his craft without incident and cautiously entered the city. As he and R2-D2 began searching for his friends, he encountered Boba Fett and a group of Imperials transporting Solo, encased in carbonite, to Fett's ship. Skywalker, hoping to remain undetected, quietly followed the group for a short time until they disappeared from sight. As Skywalker prepared to continue through the city, Fett suddenly reappeared and fired upon Skywalker, who ducked around a corner to evade the shots.
After firing a few deterring blaster bolts, Fett disengaged and Skywalker, not knowing what Fett's cargo had been, did not attempt to follow him. Shortly after, he encountered Organa and Chewbacca, who were being escorted to Vader's flagship as prisoners. The stormtroopers escorting the pair began shooting at Skywalker, who took cover again. Organa saw him and, aware of Vader's trap, desperately tried to break free of the grip of an Imperial officer in an attempt to warn Skywalker. As the group of Imperials with Organa broke off the fight and dragged her away, Luke attempted to follow. Just as he passed through the door where Organa had disappeared, it slammed shut behind him, cutting him off from R2-D2. Making his way through the catwalks and elevators of a gas-processing vane in the lower levels of Cloud City, he eventually reached the dimly lit carbon-freezing chamber. Suddenly, the chamber lit up, revealing Darth Vader, standing atop a flight of steps to the walkway above. Vader claimed that while the Force was with Luke, the boy was not a Jedi yet. Striding up to the Dark Lord, Skywalker ignited his lightsaber. Vader responded by calmly activating his own saber, and the duel began.

Skywalker initiated the duel with two quick, unsuccessful attacks aimed at Vader's torso. He then attempted an overhead strike, but the Sith Lord blocked the attack with a one-handed grip on his weapon. Skywalker's assault resulted in a blade lock, which Vader broke by casually pushing Skywalker to the floor. Skywalker quickly regained his footing and advanced, engaging in an aggressive series of attacks as Vader retreated. However, Vader soon counter-attacked and forced Luke back to the head of the stairs. During a subsequent pause in the duel, Vader complimented Skywalker on his swordsmanship, and Luke arrogantly agreed. As he spoke, Skywalker attacked Vader again, but after a few strikes Vader disarmed him with a quick flourish.
Vader then lazily slashed at Skywalker, hoping to herd him towards the carbon freezing pit. Skywalker dove out of the way of the attack and rolled down the stairs to the freezing chamber's main platform. Vader jumped after Skywalker and held him at blade-point just beyond the edge of the pit. As the pit was closed and Skywalker's attention was focused on his opponent, the young Jedi did not perceive Vader's trap. Vader then claimed that Skywalker's destiny lay with him, and that Obi-Wan had known it. As Skywalker denied this, Vader continued to walk Luke towards the now-open freezing pit and Luke, not realizing that the pit had opened (or indeed that it was even there), continued to retreat. As such, when Vader performed another casual swing of his weapon, Skywalker backed right over the lip of the pit and fell in. Vader immediately activated the chamber with the Force, remarking that his victory had been disappointingly easy. But before the freezing process could begin, Skywalker used the Force to leap out of the pit and grab onto the hoses above it. Vader then approached the pit, contemptuously musing that Skywalker was not as strong as he had been told, when he heard a metallic crash from above and noticed Skywalker trying to climb the tubing above the pit.

Complimenting Skywalker's escape, Vader slashed one of the hoses in an attempt to dislodge his opponent, triggering alarms that started blaring through the chamber. Skywalker jumped down, grabbed the severed hose, and used it to spray gas into Vader's masked face. With the Sith Lord momentarily stunned, Skywalker used the Force to summon his lightsaber to his hand. He re-engaged Vader and locked blades with him again. Vader taunted Skywalker, asserting that, while he had control of his fear, unleashing his anger was the only path to victory.
The Sith Lord broke the blade-lock and attacked. Skywalker managed to fend off Vader's onslaught, flipping over the Sith Lord to avoid an attack at his legs. Landing behind Vader, Skywalker went on the offensive and drove the Sith Lord to the edge of the platform, kicking Vader in the abdomen. Vader toppled over the edge of the platform and disappeared from sight. Seeming to have gained the upper hand, Skywalker jumped down after Vader.
Searching for the Sith Lord, Skywalker wandered through a tunnel into the city's processing vane, which overlooked a deep, low-pressure reactor shaft. There, he encountered Vader, standing with his weapon ignited at the far end of the chamber.

As Luke began to haltingly advance on his opponent, Vader telekinetically tore a fixture of metal pipes off of a wall behind Skywalker and threw it at him. As Skywalker turned and cut the fixture apart, the Sith Lord lunged, engaging Skywalker in a brief bout of swordplay. As the pair locked blades, Vader used the Force to throw a metal box at Skywalker, which smashed into the back of his head and broke the blade-lock. Vader then pulled back and began telekinetically pummeling Skywalker with various objects in the room.
As Skywalker failed to hold off the improvised missiles, a misdirected piece of piping smashed through a large observation port behind him. The chamber immediately and violently depressurized, sucking Skywalker out into the reactor shaft while Vader grabbed a nearby wall for support. As the pressure equalized, Vader went to the shattered observation port and observed that Skywalker had managed to grab the railing of a catwalk several floors below.
Skywalker climbed up onto the catwalk and again began searching for Vader. Eventually, he entered a narrow corridor in the processing vane, where he was ambushed by Vader. The Sith Lord engaged in a ferocious series of overhanded strikes, which forced Skywalker onto the defensive. Overwhelmed by Vader's strength, Skywalker was rapidly driven back through the corridor. Blade-locking with the boy, Vader threw him against a wall and slashed at him, but Skywalker recovered just in time to avoid Vader's attack. The attack struck the wall behind Skywalker and showered the corridor in sparks. After dodging another such attack, Skywalker attempted to retreat along the catwalk from whence he had come but Vader quickly cut him off. Shoving Skywalker onto the dead-end that was the central catwalk, Vader continued his relentless assault. Blocking or shunting aside everything Skywalker threw at him, Vader soon blade-locked with the youth one final time and pushed him to the ground.

Putting his saber at Skywalker's throat, Vader proclaimed the boy defeated, and told him that further resistance would end in Skywalker sharing Kenobi's fate. But Skywalker defiantly drove Vader's weapon aside and regained his feet. As they renewed their fight, Skywalker managed to slightly wound Vader's right shoulder with a desperate swing before retreating. Enraged by the breach in his defenses, Vader moved to end the duel, driving Skywalker to a small extension at the end of the catwalk. There, Vader sliced apart a piece of equipment on the catwalk, parried Luke's weapon hard enough to expose his wrist, and sliced off his right hand with a swift undercut. Both Luke's hand and his lightsaber fell into the depths of the reactor shaft.

As Skywalker recoiled with a scream of pain, Vader deactivated his weapon and began conversing with Skywalker. While Skywalker retreated to the end of the extension, Vader attempted to sway him to the dark side, promising him that the two of them could end the Galactic Civil War and bring order to the galaxy. Skywalker refused, but Vader then revealed to him that he had formerly been Anakin Skywalker, Luke's own father. Though Skywalker vehemently denied the claim, as Kenobi had told him that Vader had betrayed and murdered Anakin, he sensed with all his heart that Vader was telling the pure truth. Though shocked and horrified, Skywalker found the courage to jump off the catwalk to a seemingly certain death rather than betray his Rebel fellows and join the Empire. As he fell, Skywalker was sucked through a number of vents, which eventually deposited him on a weather vane below Cloud City. Badly injured, exhausted and mentally spent, he called out to Kenobi for aid but received no reply. He then desperately attempted to contact Organa through the Force.
Unbeknownst to Skywalker, Lando Calrissian had switched allegiances to the Rebels in response to Vader changing the terms of their agreement several times. Realizing that Vader could not be trusted to keep his word, Calrissian had freed Leia and Chewbacca and they attempted to retrieve Solo from Fett. Although they failed to do so, they had managed to reach the Falcon and escape the city. While on their way to leave Bespin, Organa heard Skywalker's mental cry for help and ordered the freighter around to rescue him.
As the crew of the Falcon recovered Skywalker, Vader arrived at his flagship, the Executor, and pursued the freighter. As the Falcon left Bespin's orbit, the crew attempted to jump to hyperspace, only for the hyperdrive to fail once again. As the Executor closed in, panic set in on the Falcon as the rebels desperately attempted to discover what was wrong with the supposedly repaired hyperdrive. As the freighter evaded a small group of TIE fighters, Vader telepathically contacted Skywalker and attempted once more to turn him to the dark side. Skywalker continued to struggle with Vader's revelation, particularly with the fact that Kenobi had failed to tell him the truth. With the rebels unable to figure out why the hyperdrive of the Falcon was not functional, the Executor closed and prepared to tractor the freighter. However, R2-D2 had discovered during the escape from Cloud City that the Falcon's hyperdrive had in fact been repaired, and that Imperial agents had simply deactivated it. The astromech droid quickly reactivated the drive, and the Falcon lurched into hyperspace just before the Imperials could activate the tractor beam.
Despite Vader's tendency to execute Imperial officers who had failed him on the spot, Vader spared Admiral Firmus Piett, the CO of the Executor, and strode from the bridge in silence. Meanwhile, the Falcon rendezvoused with the Rebel fleet, where Luke was fitted with a prosthetic hand that was visibly indistinguishable from his original one (he would later construct a new lightsaber to replace his lost weapon as well). As his operation was concluded, Calrissian and Chewbacca left aboard the Falcon for Tatooine with the intent of locating Solo in order to free him. Vader's revelation haunted Skywalker, shaking his faith in Kenobi and destroying the image of the father he had thought he had.

During the battle over Jekara, Skywalker realized he was not yet to duel Vader again and instead lured him into a starfighter chase over the planet. About a year after the Cloud City duel, Luke had managed to come to terms with his parentage, and even thought to use it to convince Vader to return to the light. During his confrontation with Vader and the Emperor on the DS-2 Death Star II Mobile Battle Station during the Battle of Endor, he managed to do just that. Redeeming himself, Vader defeated the Emperor and died from his wounds, bringing balance to the Force and fulfilling the prophecy of the Chosen One which Qui-Gon Jinn believed he would fulfill years ago.
In 28 ABY, Leia cited the duel between Luke and Vader as one of the main reasons for which she couldn't forgive her father, even posthumously, to Senator Ransolm Casterfo from Riosa. In 34 ABY, the Force-sensitive scavenger Rey discovered Skywalker's original lightsaber in the basement of Takodana Castle, having been recovered by Maz Kanata through secretive means. Upon touching it, Rey had a Force vision, in which she appeared in the corridors of Cloud City and witnessed the duel of Vader and Skywalker.

The Duel on Cloud City is featured in the 1980 film Star Wars: Episode V The Empire Strikes Back, which is the second movie in the Star Wars original trilogy. Many fans, including 501st Legion founder Albin Johnson, consider the duel to be the most memorable lightsaber duel in Star Wars history, and perhaps the best remembered scene of the original trilogy.
George Lucas wanted the lightsaber fights to become "faster and more intense" as Skywalker became better at using a lightsaber, so a shift in dueling style became evident. Some one-handed fighting forms made their first appearance, giving a glimpse of what lightsaber duels of olden times would eventually be revealed to look like.
The revelation of Skywalker's parentage was a closely guarded secret. Even David Prowse, the actor who physically portrayed Darth Vader and spoke the lines on set, was unaware of the truth, because the film's crew feared he might reveal it in an interview. While it is said that Prowse spoke the line "Obi-Wan killed your father," which was printed on a substituted page of the screenplay, Prowse himself revealed in April 2006 that he never actually said that line. Instead, Prowse said "Come and join me and the Dark Side." However, he believes that the revelation of Luke's parentage was a wonderful twist. The overdubbed voice of James Earl Jones spoke the true line. Mark Hamill himself was only informed moments before filming the scene, and no one else in the cast besides Jones and Hamill knew until Episode V's premiere.

One of the initial concepts for Rey's Force vision in the 2015 film Star Wars: Episode VII The Force Awakens involved Rey witnessing the duel on Cloud City. However, the idea was scrapped because director J.J. Abrams wanted it to be a more personal story filled with incomprehensible elements, such as the Knights of Ren or her first time on Jakku. This idea was retained in Alan Dean Foster's novelization and Michael Kogge's junior novel, both of which included segments where Rey witnessed a small portion of the duel in her vision.
The extensive efforts made by the production team to prevent the identity of Skywalker's father from being leaked to the public were eventually parodied in The Simpsons episode "Worst Episode Ever." In the episode, Mrs. Prince unwittingly sells invaluable Star Wars memorabilia to Comic Book Guy, including a film reel labeled "Alternate Ending: Chewbacca is Luke's Father."