The Ugnaught rebellion represents an insurrection that transpired within Cloud City, situated on the planet of Bespin. This event occurred shortly after the Battle of Hoth.
Lando Calrissian, who formerly held the position of Baron Administrator of Cloud City during the era of the Galactic Civil War, was compelled to abandon his post due to an Imperial occupation. Additionally, he sought to rescue his captured associate, Han Solo, from the clutches of Jabba the Hutt. Following his departure, Cloud City and the tibanna gas extraction operations on Bespin were seized by the Empire. The Emperor then dispatched an Imperial Navy officer, specifically Captain Hugo Treece, with orders to assume control over the city, its gas processing infrastructure, and, by extension, the entire planet.
Captain Treece subsequently became entangled in an embezzlement scheme that was unfolding within the city. In an attempt to conceal irregularities in his financial activities, he sought to reduce labor expenses in Cloud City by subjecting the city's Ugnaught population to enslavement.
After a relatively brief duration, the Ugnaught laborers grew weary of their enslaved status and initiated an uprising. This rebellion was spearheaded by the affluent King Ozz. The revolutionaries infiltrated the lower levels of the refineries and strategically placed twelve talking bombs at various locations throughout the city. They informed Captain Treece of their scheme, granting him an opportunity to evacuate the city. However, Treece directed the cyborg aide Lobot to access the central computer and temporarily disable all of the bombs.
Shortly thereafter, King Ozz was reunited with Calrissian. Lando became aware of the Ugnaughts' enslavement and pledged his assistance in liberating them from Imperial occupation and bondage. They embarked on several floatboats and set out from the marshland settlement of Ugnorgrad, heading towards Cloud City itself.
Simultaneously, Luke Skywalker and Shira Brie also arrived in Cloud City. They located the Imperial garrison and engaged in combat with Captain Treece's stormtrooper forces.
Luke Skywalker employed the power of the Force to activate the primers on all of the talking bombs. However, this action did not trigger the actual detonation of the bombs. Treece and his subordinates mistakenly believed that the bombs had exploded and that Cloud City was on the verge of falling into Bespin's core. Treece issued an order for a strategic retreat, and his Imperial regiment abandoned the planet, thereby ending the enslavement of the Ugnaught tribes. The Ugnaught holojournalist, Ars Fivvle, documented the concluding moments of the epic conflict from the front of his floatboat. Ars' journalistic contributions to this historic event earned him widespread recognition across the planet.
Following the cessation of hostilities, Lando instructed Lobot to access Captain Treece's bank accounts on Aargau. He proceeded to transfer a substantial portion of Treece's embezzled funds and re-deposited them into Darth Vader's personal banking account. This action effectively exposed Treece's clandestine activities to the Emperor. Upon discovering Treece's involvement, Emperor Palpatine ordered his immediate execution.