This was written for Whumptober Day 1:

No. 1 - ALL TRUSSED UP AND STILL NOWHERE TO GO
"You have to let go" | barbed wire | bound

Warning for major character death.

"Why would Palpatine set up shop here?" Luke had to wonder, wrinkling his nose. When he'd agreed to help his father kill the Emperor, he hadn't expected himself to be taken to such a horrible place.

Well, no, that wasn't quite true. Horrible was a prerequisite for the Sith. But the all-consuming sense of darkness around them aside, a lava planet seemed a little excessive.

"He is not the one who chose this location," Vader rumbled. He seemed… distracted, scanning the lava fields in the distance with a singular focus. The shields just on the outside of the parapet they were walking along flickered menacingly. "I did."

"You decided you wanted your final battle with your master to be on a lava planet?"

"My final battle with my previous master was on a lava planet," Vader snapped back. "Obi-Wan cut off all my organic limbs and left me to burn on that shoreline." He jabbed a finger in the distance and Luke turned, wincing as the patch of black rock he was pointing at crumbled into the fire.

"That must be a horrible way to die," he murmured.

"It was an excruciating way to be reborn," Vader corrected. "But I rose from the ashes nonetheless. Pain gives a Sith his power."

Luke privately thought his father may need medical attention—for both his body and his mind—if he wanted to truly heal, but he would bring that up once Palpatine was dead. Until then, the bond between them would be the most cancerous thing, sending darkness and doubt into the heart of his father's psyche by merely existing.

"You will learn that in time, my son," Vader added, and Luke scowled. That was another argument they would have to deal with.

"Palpatine must know we're coming," he said instead, changing the subject. "He will be prepared."

"He will be. But I have spies in his court and guards, and above all he is arrogant. He wants you in the darkness, under his thumb. He will not attack us until the fatal moment; he will instead try to twist your mind until you serve him. And only him."

"I see." They reached the end of the parapet, and turned to enter the castle. "And he won't just kill me if he sees me as a threat?"

"He may," Vader conceded. "But it is unlikely—"

The shields flickered out.

Luke gasped in shock at the heat that pummelled him, the sudden flood of toxic gases that the shields had been keeping at bay filling his lungs, setting them on fire from within. He stumbled to the side, grasping the thick wall of the parapet with both hands as his legs buckled, his head spinning from the poison. The world was nothing but a blur of black and gold.

"Luke!" Vader surged for him, hand outstretched, but the next great splash of lava shattered against the wall and flared over it. The bricks glowed and crumbled and Luke screamed as molten drops hit his skin, flesh running through red to black to sagging and dead within minutes…

Vader had jerked back, but now he gritted his teeth and came forwards again, reaching for his sobbing, wailing son. Luke was leaning full on the wall, shaking, burning.

"Luke—"

Another splash came, and those that had been so wondrous to stare at from behind the safety of the shields were terrifying without them. The parapet gave way.

Luke went with it.

"LUKE!"

All he knew for a few seconds was heat, terror and pain, eyes dazzled by the blinding fire that cocooned around him in a deadly embrace. Then he was caught in mid air and it rained around him. He cried out as some of it rained on his arms again, catching fire, but a cold, metaphysical hand pressed the flames out.

"Luke," Vader said again, like it was all he knew how to say. He was staring at him in pain.

Luke was in pain too. He couldn't open one eye but he trained the other on his father.

"Luke, I've got you. Do not worry. I have you." Vader extended two arms and held Luke there, pulling him closer.

Then a shadow flickered behind Vader. The doorway into the castle was filled by a hooded figure, and his hands crackled blue.

"Father," Luke choked out, but his voice was too quiet to be heard.

Vader didn't listen. So when Emperor Palpatine brandished lightning like a sword and struck him in the back with it, he fell to his knees.

Luke fell metres before he was jerked to a halt again, horribly close to the surface. Vader was staring down at him from the ruined walkway, his mask expressionless but the Force booming with terror, and when the corona of blue light surrounded him again he buckled but held onto Luke like Luke was the anchor, not him.

"Did you think that your motions were unknown to me, Lord Vader?" came the Emperor's rasping voice, and Luke had the horrible thought that this might be the last thing he ever heard. "Did you think you and your spawn could catch me unawares? The boy may be powerful, a novice could sense that… but I have not succeeded thus far by gambling everything on unnecessary risks."

Luke tried to yell something, but every breath pumped horrible gas into his lungs, the lava was releasing it like smoke, and it was a battle to stay conscious.

"I will kill you," Vader promised.

"I doubt it," came the sneering reply. "And even if you did, it would be too late for him. Or you."

The next barrage sent Vader slamming into the remaining wall of the parapet again. His hand still outstretched, he glanced down at Luke, as though to remind himself what he was still fighting for.

Father, Luke tried, probing the bond that would never have the chance to grow. You need to beat him. You need to kill him.

He got no response but anger, fear, horror, anguish, a deep, unrelenting despair—

No, came the reply a few moments of torture later. Do not suggest this.

You need to save the galaxy, Luke insisted. It wasn't the stinging in his still-open eye that had a tear paint his cheek. You need to fight him.

You need to let me go.

Vader roared out loud. Palpatine cackled. I will not! He was brought to his knees, bowing over in pain.

Fight back, Father, Luke commanded. Then he added, I love you.

He seized the Force—light or dark, it didn't matter now, at the end—and threw it at his father, sending him stumbling back, away from the lightning. Away from Luke. In that split second of confusion, Luke fell.

He hit the lava before he heard his father's reply.