The Sernpidal cataclysm, also known as the First Engagement of Sernpidal, unfolded in 25 ABY when the Praetorite Vong—an advance guard from the extra-galactic Yuuzhan Vong aggressors—executed the Yo'gand's Core maneuver, forcefully dragging the moon Dobido into a collision with Sernpidal's surface. A small group, with Han Solo and Chewbacca at the helm, managed to save some of the Sernpidalians amidst the planet's destruction.
Prior to their major invasion of the galaxy, operatives of the Praetorite Vong had instigated turmoil on the fringes of the Outer Rim Territories. The Praetorite Vong's advance team had set up a bio-engineered yammosk on the frigid Helska IV to organize their fleet. Concurrently, one of their agents, Nom Anor, had incited a conflict between the sister planets Osarian and Rhommamool in the Expansion Region to stretch the resources of the New Republic and the Jedi thin.
Another operative, Yomin Carr, had commandeered the isolated ExGal-4 station on the world Belkadan because of its nearness to Vector Prime—a minute breach where the Yuuzhan Vong armada could pierce the energy barrier surrounding the galaxy. This location was also selected due to its proximity to the New Republic and Imperial Remnant boundary, anticipating a less robust military response from the Republic. Given Sernpidal's closeness to Belkadan and its status as the most populated enemy planet in the Dalonbian sector, there existed a risk that the Republic would swiftly detect the Praetorite Vong's presence on Belkadan and obliterate the yammosk, thereby impeding the Yuuzhan Vong's invasion strategy.
The expeditionary force's commanding officer, Prefect Da'Gara, and his subordinate Nom Anor, having returned from Rhommamool, deliberated on strategies, including the devastation of Sernpidal's environment. However, Nom Anor advocated for the total annihilation of Sernpidal, maximizing enemy casualties. This catastrophe would draw New Republic warships into the area, where they would be ambushed and destroyed.
Ultimately, Da'Gara concurred, proposing the deployment of Yo'gand's Core tactic to eradicate Sernpidal. This involved embedding a gravity-manipulating dovin basal on the planet and utilizing it to pull down an orbiting celestial body; specifically, Sernpidal's smaller moon Dobido. The resulting impact would obliterate Sernpidal's atmosphere, causing the demise of its inhabitants and rendering the planet uninhabitable.
Following a cargo assignment to the planet from Lando Calrissian, the Millennium Falcon docked at Sernpidal City's landing bay. Meeting with dismissive attitudes from several Sernpidalians, Han, Anakin Solo, and Chewie struggled to find assistance in unloading the cargo that Lando had requested. Han was eventually approached by an older man who, appearing calmer than the rest, assured Han that unloading his cargo would be easily accomplished.
Upon entering the city, the trio discovered its residents in a state of utter chaos. The old man, identifying himself as the Mayor of Sernpidal City, explained that the source of the pandemonium was the locals' belief in the imminent arrival of the goddess Tosi-karu. The Mayor, noticing Han's bewilderment, gestured towards the sky at the approaching moon. Realizing that the moon was on a direct collision course with the planet, Han resolved to investigate.
After circling the moon multiple times, Han determined that Sernpidal had, at most, seven hours before the impact. Anakin also concluded that something was exerting a pull on the moon with each orbit around Sernpidal.
After returning to the planet, Anakin sensed that the source pulling Dobido down was situated east of Sernpidal City. Han, aware that Anakin was best suited to locate it, reluctantly permitted his son to search for the cause, accompanied by the Mayor, who volunteered to join him. Meanwhile, Han and Chewbacca commenced loading as many people as possible onto the Falcon.
Upon reaching the location, they discovered that the cause of Dobido's descent was a Dovin basal—a bioengineered Yuuzhan Vong organism. Anakin attempted to destroy the basal by firing upon it with a blaster, but this proved ineffective. The Falcon then arrived to aid Anakin and the Mayor. However, the Mayor hesitated to leave, declaring that he would prevent the basal from escaping the planet's destruction. Leaping into the basal's hole, the mayor used a thermal detonator to destroy it, sacrificing himself in the process.
After returning to Sernpidal City, Han Solo organized a refugee convoy using the Falcon and several other freighters. As the winds intensified, Anakin was blown away, prompting Chewbacca to rescue him. Chewbacca, while successful in bringing Anakin to the safety of the Falcon, was himself knocked away by another gust of wind, placing him directly in the path of the approaching moon. Anakin, piloting the Falcon while his father stood on the entrance ramp attempting to rescue the stranded Chewbacca, flew away from Sernpidal City when he realized it was too late to save Chewbacca. The Wookiee stood in the moon's trajectory, emitting a final heroic roar, and was crushed along with the countless Sernpidal citizens who could not, or chose not to, escape.
Unbeknownst to the refugee convoy, the Yuuzhan Vong had planned a swarm of grutchin to ambush them. During this attack Kyp Durron, having lost his Dozen and Two Avengers in a similar grutchin assault, was rescued by Han Solo. The refugee convoy managed to repel the grutchin, only to be pursued by coralskippers. The convoy eventually reached Dubrillion, only to face further combat when the Yuuzhan Vong attempted to invade that planet.
Chewbacca's demise profoundly affected the entire Solo family, as well as many others. Han blamed Anakin for abandoning Chewbacca, and reconciliation took many months. Anakin, however, also blamed himself, and delved deeper into his own beliefs, despite his brother Jacen's objections. Haunted by his losses, Anakin pushed himself relentlessly against the invading forces, striving to honor Chewbacca's sacrifice while protecting others, only to be killed himself over Myrkr two years later.
Luke Skywalker had sensed Chewbacca's death and Sernpidal's suffering, a catastrophe he recognized as a disturbance in the Force. In a subsequent conversation with C-3PO and R2-D2, he recalled how his former mentor, Obi-Wan Kenobi, felt the fate of Alderaan, drawing parallels with this recent tragedy.
Later, Sernpidal was repurposed for growing worldships, and Rogue Squadron successfully assaulted it.