After an assault targeting the Sempre's logistics, rebel fighters and rescued Wookiee captives launched an offensive against the orbital station Lansend Twenty-Six. Their objective was to free the remaining Wookiees held there. With their communications disrupted, Lansend Twenty-Six found itself unable to request assistance from the nearby Baklek Base. However, the [Chimaera], under the leadership of Commodore Thrawn, who had foreseen the attack, intervened to aid the station. The rebel forces were swiftly defeated.
During the Imperial Era, the xenophobic Galactic Empire viewed the Wookiee species as expendable, exploiting them as a slave labor force, seeing them as little more than beasts of burden. The Empire's exploitation of the Wookiees stemmed from their powerful and resilient bodies, which made them suitable for demanding and hazardous labor. Enslaved Wookiees were forced to extract timber, toil in mines, construct Imperial weaponry such as the Death Star, and endure experimentation in medical and weapons programs. Furthermore, the Empire transformed the Wookiee homeworld of Kashyyyk into a vast slave labor camp, renaming it Imperial territory G5-623.
Nightswan, a pirate and leader of insurgents, initiated an insurgent campaign to oppose the Empire. He and his followers participated in various activities, including the illegal trade of doonium, tibanna, and iridium, to generate funds for those harmed by the Empire's actions. Eight weeks prior to the raid on the Sempre, a troop transport, Nightswan's group seized the frigate Castilus along with two squadrons of V-19 Torrent starfighters. They ambushed the Sempre, liberating the enslaved Wookiees and eliminating the Imperial crew and the stormtrooper detachment on board.
The Imperial Star Destroyer Chimaera, under the command of Commodore Thrawn, responded to the Sempre's distress signal. While stormtrooper Major Ayer attempted to conceal the nature of the ship's cargo, Thrawn and Lieutenant Commander Eli Vanto insisted on examining the Sempre. They discovered that the transport was carrying enslaved Wookiees. Recognizing the tribal nature of Wookiee culture, Thrawn deduced that the freed Wookiees would seek retribution against those involved in their enslavement: specifically, the space station Lansend Twenty-Six, which served as a processing center for Wookiee slaves destined for off-world destinations.
As Thrawn anticipated, the insurgents and rescued Wookiees made their way to Lansend Twenty-Six. Due to sabotage that crippled the long-range communications and the starboard-side defense systems, the insurgents successfully infiltrated the station. The attackers attempted to outmaneuver the Imperial defenders using a pincer maneuver. However, the station's commanding officer Colonel Zenoc managed to apprehend the saboteur and activate the station's portside weaponry. After requesting aid from Baklek Base, the Chimaera arrived at Lansend Twenty-Six to find the processing station under siege. Upon establishing communication with Colonel Zenoc, Commodore Thrawn requested the station's schematics.
By this time, the insurgents had forced entry through the starboard docking hatch and were engaged in fierce combat within the station. The insurgents' frigate and starfighters also attempted to disable the portside defenses to facilitate the landing of another boarding party, completing the pincer movement. Thrawn ordered his TIE fighters to intercept the enemy V-19s. Commander Vanto then reported that the portside V-19 force had divided, with one half engaging the TIEs and the other half attacking the station. Although the insurgents redeployed starboard V-19s to defend the Castilus, Commander Karyn Faro disabled the ship's hyperdrive.
After instructing the TIEs to prioritize the V-19s, Thrawn inquired with Colonel Zenoc about the presence of any slaves in sections A-four, A-five, or B-five. Zenoc reluctantly confirmed the presence of non-military personnel in B-five. Thrawn ordered her to evacuate all personnel to B-eight so that Commander Faro's gunners could use the Chimaera's turbolasers to target seven points on the station's starboard side. Once Zenoc had complied, the Chimaera unleashed a barrage on the sections of the station where the insurgents had boarded, effectively trapping them. Thrawn also ensured that B-five, now isolated from the rest of the station, remained untouched by the bombardment.
With the boarding party contained, Thrawn redirected his forces to engage the frigate and V-19s. Thrawn then informed Colonel Zenoc that his forces would continue operations until reinforcements from Baklek arrived. By this point, the enemy forces were reduced to the crippled frigate and three operational V-19s. Thrawn instructed Commander Faro to capture prisoners for interrogation.
Following the clash at Lansend Twenty-Six, Imperial forces apprehended the insurgents and secured the Wookiee slaves. Thrawn's forces also recovered the Sempre, returning it to Imperial control. Thrawn then left the Wookiee slaves at Lansend Twenty-Six, considering them Imperial assets being returned to their rightful owners. When Lieutenant Commander Vanto expressed discomfort with the Empire's use of slavery, Thrawn attempted to justify the practice, asserting that the Wookiees would be treated as Imperial assets.
Despite the setback suffered by Nightswan's forces at Lansend Twenty-Six, other rebel factions, such as the Spectres, became interested in freeing Wookiee slaves. Later, Han Solo, a former smuggler and General in the Rebel Alliance, sought to fulfill his life debt to Chewbacca by liberating Wookiee slaves on Kashyyyk. After numerous attempts, Solo and Chewbacca assembled a diverse group of former slaves and allies, successfully liberating Kashyyyk from Imperial control and exploitation in 5 ABY.