Probes were launched everywhere across the Galaxy to search for the relocation of the Rebel base, and (in Darth Vader's mind) to find Luke Skywalker, Darth Vader's son, and what remains of his chance to know his family. One fateful Imperial probe landed on Hoth, and detected a settlement. Darth Vader was convinced that this was the Rebel base, and instructed his ship Executor, among other Star Destroyers, to head for the system.
Meanwhile, Luke Skywalker was reunited with Han Solo, Princess Leia, Chewbacca, C-3PO, and R2-D2 after an encounter with a Wompa Ice Creature and bitter cold. As the Imperial forces showed up over Hoth, the Rebellion prepared for an attack on the invaders. The plan was devised: ground forces would defend the planetary shield generator from small landed forces as a starfighter squadron would distract the Star Destroyers. The ion cannon would fire at the Imperial Star Destroyers just enough for the starfighters to take out their shield generators and destroy their command decks. Rebel Transports, piloted by a minimum crew, would distract the fire from the Star Destoyers and circle around at top velocity to avoid fire.
Landing craft were encountered by the starfighter squadron that was launched to combat the Star Destroyers. Several landing craft were taken out, while others were able to let out their AT-ATs and AT-STs. The walkers approached the shield generator, and were met by platoons of snowspeeders led by Commander Luke Skywalker. The AT-ATs' weaknesses were found: their "necks" were not heavily armored, so they could be shot at from high above at that area. This proved to be effective, especially if the speeders shot from behind. Nearly all of the AT-ATs were taken down and the AT-STs were efficiently combated by the turret placements and assisting snowspeeders.
The starfighters sent to combat the Star Destroyers reached orbit and made themselves noticed by the nearest Star Destroyer. TIE Fighters were launched from the Star Destroyer's docking bays and were sent to combat the fighters. The two squadrons fought, and the ion cannon on the surface fired several shots, successfully disabling the capital ship temporarily. The rebel fighters closed in on the Star Destroyer, ignoring the TIE fighters for only a manner of seconds, and were able to destroy the shield generators and command deck of the Imperial ship in one attack run.
Meanwhile, a second, much more populated wave of AT-ATs and AT-STs made their way to the Rebel shield generator. Darth Vader rode with the landing craft to the surface, and advanced ahead in his TIE Advanced Fighter. Once he met up with the first wave of walkers, which were being mercilessly defeated, he spotted a snowspeeder with a slightly familiar presence: his son. Darth Vader saw that Luke was acting far too boldly in the battle, and was bound to get himself killed if he persisted against the AT-ATs. Darth Vader was then contacted by Admiral Ozzel, who asked him to destroy the Rebel's shield generator. Darth Vader hesitated, knowing that if the shield went down, the Imperials would mercilessly kill everyone in their path, including the last remnant of Vader's love. Vader desperately looked for a way to avoid the task he was asked to perform, and in his haste, his TIE Advanced was shot down in the crossfire. Vader said he was down, and the AT-ATs would have to make the run.
The Rebel fleet took down the next Imperial Star Destroyer and found the Executor, which they were ordered to combat. The fleet deployed their weapons, and concentrated all fire on the Super Star Destroyer. At maximum firepower, the shield generator of the massive ship was compensated. The fleet moved in, and the Imperials inside the Super Star Destroyer panicked. They jettisoned escape pods with their crew and sent out the massive wings of TIE Fighters. The crew desperately tried to evacuate the spaceworthy fortress. As the Rebel fleet was now able to close in, serious damage was done to the Super Star Destroyer, and the Emperor, who was on the ship for some weird unknown reason, was blocked from accessing his designated Star Destroyer and was forced to be escorted by Admiral Viette to the Lambda-class Imperial Shuttle. The shuttle caught the eyes of the Rebel fleet, and the frigate Redemption and two Rebel Transports were sent after it, pursuing the shuttle to the asteroid field.
Darth Vader survived the crash landing and made it to the shield generator on foot. He had seen Luke's speeder get hit, and in his horror, did not figure out that Luke's presence remained in the speeder. Darth Vader, angered by his guilt and despaired by yet another loss, sped towards the Rebel shield generator and planted thermal detonators in it after cutting a hole in it with his lightsaber. The shields blew, but the AT-AT reinforcements were still yet kilometers away. Darth Vader, now being approached by Rebel troops, fled the scene and was able to get to a downed TIE fighter and maneuver it back to the Imperial fleet.
The Executor was being slaughtered by the oncoming Rebel fleet. Finally, after commander Dac surmised that he felt like he could take on the entire Empire himself, charged by himself towards the Super Star Destroyer's command deck. "BLEAH! HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHAHA...uh-oh," he said as turbolaser fire hit his A-Wing and he crashed into the Star Destroyer's command deck. The massive ship, damaged severely, had its orbit altered and it crashed into the planet Hoth. The Rebel fleet retreated back to Echo Base.
The second wave of AT-ATs were approaching the base, with the shields down, all that had to be done was to eliminate the Rebels from the settlement. Then a dark shadow loomed over the walkers. Nothing could stop it; the Super Star Destroyer collided with the planet, destroying the AT-AT army, but was too far from the Rebel Base to do significant damage. Luke Skywalker made his way back to the base. The Rebels relocated because the Empire knew their location, and the Emperor conversed with Darth Vader. Darth Vader learned that Luke was still alive, and his hatred toward the Emperor grew. He suggested that Luke be turned to the Dark Side, and Palpatine agreed. With that settled, a plan was concocted to turn Skywalker to the Dark Side.