Luke Skywalker's lightsaber slid slowly down Darth Vader's. The Cloud City facility was completely silent aside from the hum of the two weapons and the sound of the Dark Lord's respirator, as well as Luke's own light breathing.
"Obi-Wan has trained you well," Vader said in his deep, mechanical voice. "But you are still no match for the dark side! Your powers are weak."
Hatred boiled up inside of Luke. He let out a scream of outrage as he whipped his lightsaber towards the Dark Lord, who easily blocked him. He struck again and again in relentless anger, but Vader proved to be the stronger in the end, using the Force to propel Luke away.
Vader lifted a metal crate into the air, and sent it at Luke, who swung his lightsaber to block it. Two more crates found themselves flying towards the young man, and he blocked one, the other missing him by a mere centimeter. However, Luke still swung at the one that had missed, and got hit squarely in the chest by another. Skywalker turned to attack another, but missed, and was soon barraged with a storm of crates. Moaning in pain, a bloody Luke managed to duck underneath another crate, which broke a facility window. Air began to suck everything in the chamber out, and Luke was soon sucked up by the vacuum as well.
He fell down further and further until he reached a platform. As he passed by it, Luke grabbed the edge of the catwalk and hauled himself up, attempting to still his breathing. He had evaded Vader, but not for long. The Dark Lord was probably on his way.
As if on cue, Luke could hear the noise of Vader's ventilator just before he felt the red lightsaber whiz past his ear. Luke brought up his own 'saber in defense, and parried a few blows, but a sudden pain urged throughout his arm, and his lightsaber dropped below the catwalk and out of reach. Luke cried out in pain, and looked down at his arm. His hand was cut off at the wrist. Blood seeped out of the open wound, spilling over the metal and covering it in red within seconds.
"You don't know the power of the dark side!" Vader insisted. "Come with me, Luke, I'll teach you everything you need to know."
"I'll never join you," Luke screamed, and spat at Vader's mask, only to have the saliva come a good meter short. "You killed my father!"
"Ah, Obi-Wan never told you the truth. I never killed your father, Luke. I am your father."
Luke reeled. "No," he said. "That's not true!" he said. Then he screamed, more to himself, to stop the dizzying revelation and bring out the lie that he had believed. "THAT'S IMPOSSIBLE!!" Tears of agony, frustration and denial welled up in his eyes and ran out, mixing with the drying blood caked on his face.
"Search your feelings, Luke, you know that it is true," Vader said. And Luke knew he was right. "Come," the Dark Lord insisted. "Learn the ways of the Dark Side. Join me and we can overthrow the Emperor and rule together as father and son! We can make things the way that we want them to be!"
Luke dropped to his knees, clutching his injured arm. "Father…" he said. "How could we do this?"
Vader drew another lightsaber other than his own, and activated it. He barely touched each of Luke's shoulders with it, then handed the weapon to his son. "To begin your path on the dark side, you must complete a task that will show me where your true allegiances lie."
Conflict raged within Luke. Part of him wanted to take his new blade and strike down Vader with all of his hate and might. Another part wanted to run, to go back to the Rebels if he possibly could. And yet another part of him wanted to see what his father had in mind, to make his father his Master.
Luke stood, "What is your will, Father?"
"There is only one person other than the Emperor that stand in our way. Your friend, the Princess. She is on this very planet. Destroy her, and bring me her head as proof."
"It will be done, Father," Luke said, ignoring the conflicting emotions inside of him. All his life he had wanted power, and to find his father. Here they both were in one place. He walked away, his new lightsaber a reassuring weight at his hip.
"Luke," Vader said after he had gone a few paces. "Just her head."
Luke set out towards his new destiny, a dark, winding path, in which he would always make sure his Father's will be done.