The Tarkin Battle Station took the Death Star's primary offensive battery, the ionic cannon and surrounded it with a set of engines and defensive shield generators unmatched by anything that the Rebel Alliance had previously encountered. This new instrument of Imperial power was assembled with secretly channeled resources. It omitted the design weakness that proved fatal to the original Death Star, thereby making any direct attack upon the Tarkin to be suicide. During its construction phase, a protective fleet that (temporarily) included the Death Squadron held a watchful eye over this new demonstration of Imperial progress. In comparison, the Tarkin and its planet-shattering ionic cannon made the escorting Imperial Star Destroyers appear to be mere insects in both size and power. Orbiting the planet of Hockaleg, in the Patriim System was the drydock that was assembling the mobile battle station code-named the Tarkin. By the time of its untimely destruction, the Tarkin was behind schedule and was considered not yet operational.

    After the Battle of Bespine (post Hoth) Captain Maraba Tev, one of the Rebels' best spies managed to infiltrate and obtain the plans for the Tarkin when he was assigned to a high risk mission in the Patriim System. During his escape in a X-Wing, he was fatally injured while being pursued by a dozen Imperial warships. He died just mere seconds after managing to arrive at a temporary Rebel cruiser base. A Rebel Nebulon-B Frigate at the base recovered Captain Tev's X-Wing, and its flight crew discovered the dead pilot clutching a message canister which was immediately sent to General Rieekan. The contents of the canister answered one of the burning questions that was plaguing the Rebels; why had the Empire yet to construct a second Death Star (unbeknownst to them at the time, the Empire was indeed in the process of constructing the Death Star II).

    Due to the Tarkin's invulnerability to a direct assault, the Rebels decided to sabotage the mobile battle station from within. Thus those Rebels who had set foot within the original Death Star's confines (Luke Skywalker, Princess Leia Organa, Chewbacca, C-3P0 and R2-D2) were volunteered for the task. Unknown to them, Lando Calrissian had secretly included himself in the Rebel team by stowing away in one of the Millennium Falcon's smuggling compartments. The Rebel sabotage team traveling onboard the Millennium Falcon somehow managed to convince the Hockaleg (Imperial garrisoned) spaceport that they were "a spice freighter in need of repairs" in order to gain permission to land. Once on Hockaleg, the Rebels managed to infiltrate the construction crew and board the Tarkin via a transport shuttle, through a combination of stolen uniforms and Force mind tricks. In all, the Rebels were only armed with heavy blaster pistols and a single proton grenade. Their plan was to make their way to the Tarkin's main reactor undetected, destroy it with a single proton grenade, and escape using escape pods located in the station's escape pod bay.

    Onboard the Tarkin, Lord Vader detected Skywalker's presence and thus made arrangements to ensure a confrontation between the two. To this end, Lord Vader ordered Captain Voal to remove all the security personnel guarding the main power reactor to allow Skywalker a clear path to the awaiting Dark Lord of the Sith. After being alerted to a security breach while on the Tarkin's bridge, Lord Vader kept his original plan of confronting Skywalker, but had Colonel Nord increase the guards along possible escape routes to trap the Rebel saboteurs. Unbeknownst to Lord Vader, a group of treacherous officers onboard the station which included: Captain Voal, Colonel Nord, and General Biel amongst their membership vowed to assassinate Darth Vader by the end of the day.

    At last a perfect opportunity to assassinate Lord Vader had arrived, as he had situated himself in front of the airlock in Corridor TL-37 (which oversees access to the generator room). Just as Colonel Nord was about to carry out his plan, another figure coming down from a connecting corridor, 37-A had arrived; it was Skywalker. After a slight moment of hesitation, Colonel Nord carried out his treacherous plan and opened Corridor TL-37's airlock. It seemed for a few long moments that Colonel Nord had succeeded, but with impossible strength only afforded by the Dark Side of the Force, Lord Vader prevailed from being sucked out into the cold hard death of space. Meanwhile, Skywalker who was near a freight lift managed to escape death that way, but not before losing his proton grenade.

    During Lord Vader's operation to capture Skywalker, Chewbacca and the Rebel droids made it to the power trench that housed the station's exterior tractor bean generator, which was protected by three Stormtroopers. Chewbacca was able to destroy the generator by hurling one of the Stormtroopers right into the generator's beam. Princess Leia's plan to "secure" the escape pod bay failed when she encountered an increased security presence of Stormtroopers, which forced her to flee to another section of the station. Through pure chance Princess Leia located the activating mechanism for the ionic cannon. With the aid of schematics provided by her handheld mini-scan and her memories of the original Death Star's technical readouts she began the process of sabotaging the weapon. By changing some of the activation mechanism's wiring, the Princess was able to reverse the polarity modes of the weapon's fire controls.

    Managing to make it to the aft docking bay, the Rebels succeeded in commandeering a fully fueled transport and escaped the confines of the Tarkin. Lord Vader dispatched two TIE Fighters to reel in the escaping, but minimally shielded and armed transport. Rescue from an unexpected quarter arrived to save the fleeing saboteurs. The Millennium Falcon piloted by Calrissian destroyed the pursuing TIE Fighters and took on the Rebel escapees. With this turn of events, Lord Vader decided to personally enter the fray. He would have succeeded in taking down the Millennium Falcon for if it were not Skywalker's last minute action - releasing the Millennium Falcon's water stores directly in the path of Darth Vader, which effectively disabled his TIE Advanced x1 as he hit the wall of ice. Seeing another opportunity to assassinate Lord Vader and to eliminate the escaping Rebels, Colonel Nord ordered to fire the ionic cannon. It would be his last seditious attempt, as his order caused the Tarkin to literally fire at itself, all due to Princess Leia's sabotage.