Ben started at the black monolith covered in scaffolding and constructive equipment. The tower sat atop a sheer cliff over which poured a river of magma and fire. The heat of Mustafar's lava-riddled surface burned his face-ash and sulfur stinging his eyes-and they hadn't even gotten off the shuttle gangplank yet.

A spray of magma spurted up in the distance, and the accompanying rumble came with a flood of memory.

...The Jedi are evil!

The ground rumbled fit to tear apart.

Well, then you are lost!

Ben closed his eyes against the sudden memories and the vertigo and tucked Luke further under his cloak and his own shields. "You cannot be serious."

"I am." Vader's respirator cycled, and he gave no indication he was sharing the intrusive memories. Maybe they had been burned out of him. The Sith's heavy footsteps thundered down the ramp.

Ben opened his eyes and looked down at Luke. The youngling was awake and wiggled a little against the cloak constraining him. He babbled something then twisted around, and Ben patted him gently on the back. "It's going to be all right, Luke."

He needed to stop making promises. He sighed and followed Vader off the shuttle into the castle—if a mostly constructed black spire could be called a castle. It was cooler inside, but the empty blacks halls were angular and reflected the light in harsh streaks that made Ben squint. Scaffolding held up parts of the ceiling, and the sounds of construction echoed through the space. It was hollow and stark and oppressively Dark, enough to make Ben's stomach turn.

What was Vader thinking, bringing the boy to this cursed place?

I hate you!

There was nothing here but pain.

Vader led them through two sets of doors to an empty room that looked like it might have been meant to house guests. Eventually. There was an empty central room and doors to either side that looked like they led to other empty rooms. The whole space was empty and large and cold, inhospitable as Illum. No, Ilum's harshness was at least natural. This was devoid of anything relenting or organic, any sign of comfort. No color, no bed, no chairs. At least once the door shut behind them, the construction wasn't audible.

Ben surveyed the bare room, not bothering to keep his disgust from his face. His cave on Tatooine was more welcoming. "What, am I supposed to sleep on the floor?"

"If you would rather sleep in a cell, that can be arranged."

"Oh, is this not the detention level?"

"I grow tired of your insolence, old man."

Ben swiveled to snip back, but Luke babbled again and slipped his head free of the cloak. "Bababa."

At the sight of Luke, Vader held out his arms almost as if it were a reflex. "Give him to me."

Ben clenched his jaw, and Luke grabbed his face. "Babababa." Sleep had eased the redness from the youngling's face and his eyes, but his skin looked sallow in the harsh light. The medical droid on Polis Massa had declared him born prematurely and undersized as a result. He looked it still. But his toothless smile was utterly disarming even if he was tugging on Ben's beard.

Vader's respirator clicked. "Obi-Wan—"

Don't make me destroy you.

Ben breathed slowly through the memory, careful to keep the sudden surge of grief and anger where neither Vader nor Luke would sense it. The Jedi carefully, reluctantly detangled Luke from his beard and set the boy in his father's arms. "Don't jostle him."

Vader held his son rigidly, and Luke leaned back with a frightened expression but he did not cry. Frustration spiking in the Force, Vader looked from Luke to Ben. "He is afraid of me."

"I can't imagine why."

Vader's mask was expressionless as always, but the anger radiated off him in cold waves. "It is your fault."

Luke sucked a frightened breath, and Vader loosened his grip like he was afraid of squeezing him too tightly.

Ben crossed his arms, and the pervasive sand shook free of his sleeves. It was his fault. This haze of painpainpain that bled through the Sith's presence like spilled ink. So much of him had been dissevered. Burned as he rolled down the black ash bank to the magma river below.

I hate you…

Ben shuddered at the thought of what Vader might look like under the mask. He couldn't dwell on it, couldn't allow the grief of his failure to cloud his mind. "Why am I here, Vader? We clearly have nothing to say to each other, and if you're going to kill me, I'd prefer you do it quickly instead of continuing with this farce."

"You are alive," said the Sith. "Because my son needs someone to care for him. I read-"

Ben snorted, which elicited a growl from Vader before he continued. "On the way back from Tatooine, I performed some research. Some scientist Harlow said children require physical contact and comfort for proper development. Something which I am unable to give."

He couldn't believe what he was hearing. Ben tucked his hands under his arms and stared at the Sith. "You dragged me all the way from Tatooine to play nursemaid?"

"My options are limited. I travel often and for long periods. I cannot provide—" His voice hitched like it pained him to admit it. "—the contact he requires to thrive. But my son must thrive. He is so small. And sick. I will not lose him again."

The possessiveness in his voice made Ben shiver. He'd heard that tone before, and the oppressive, dark atmosphere of the castle added worrying layer of threat to it. Ben clenched his jaw. Neither of them were in any mental state to raise a child-that was why he had brought Luke to Owen and Beru in the first place. A youngling needed stability. Care.

But Vader stabbed a finger at him, interrupting his thoughts. "You are an unfortunate necessity."

The Jedi gritted his teeth, holding back a jab about the resources of a Sith Lord being so paltry. He would need to learn self-control in earnest to stay attached to his head long enough to do Luke any good. "For Luke's sake."

"I am glad we understand each other. Now. What do you require to provide for him?"

Ben bit down the first thing that sprang to his lips—Vader would die before he admitted fault, and the Jedi had no interest in hearing his confession. If Vader confessed, Ben was afraid he might forgive him. Instead, he stung back. "You could start by controlling your temper."

Vader's respirator cycled, but he didn't spit venom back as Ben expected. Luke still eyed his father warily, tears forming at the corner of his eyes.

They stood in awkward silence for a long time until Luke began to cry again, probably from the tense aggression in the Force.

Ben sighed in frustration. "Give him back."

Vader turned his shoulder to check Ben's advance. "No. He is my son, and when I am home, he will learn to trust me."

"Then stop broadcasting or put him down, for goodness' sake. He's Force sensitive; he can feel everything."

All the rage, the dark, the pain. Vader was in pain bordering on agony, and his son could sense it all. It was painful for Ben to be so close to the Sith, even with his shields drawn as close and tight as he could make them. He couldn't imagine what Luke felt.

Reluctantly Vader put the youngling on the floor, and Luke sat and cried. Ben crouched, extending one hand, and Luke crawled toward him in tears. He caught hold of Ben's outstretched hand and—still teary-eyed—murmured something resembling Basic but signifying nothing. The Jedi squeezed his hand and extended his presence to envelope the child, edging back the dark. Luke babbled something, and the image of Beru and a soft blanket was pressed into Ben's mind. He smiled sadly. "I know, Luke."

"Should he not be walking?" Vader asked.

"I thought you researched child development."

"I had a limited database on which to draw."

"He's barely a year old. Small for his age. Perhaps that is part of it." Ben frowned. He didn't know enough about children for this. He had raised teenagers, but infants… "When did he last eat?"

The cycling of Vader's respirator. "I do not know."

"When did he last sleep?"

Another cycle. "I do not know."

Ben snapped his gaze to the taller man. "You don't know?"

"You were there as well."

"Unconscious for a good portion of it, no thanks to you. What exactly was your plan?"

"I did not have time… for a plan."

Wonderful. This was wonderful. Ben was trapped in a castle steeped in the Dark Side at the mercy of his thoughtless captor and an infant who hadn't eaten or slept in Force only knew how long. Why was he going along with this?

Because he didn't have his lightsaber. Because Luke needed someone to protect him. Because it was his fault.

Ben stuffed his frustration and fear down deep behind his own impenetrable shields where neither Vader or Luke would sense them. Still holding the youngling's hand, he rubbed his free wrist against his forehead. "A bottle. A crib. A change of clothes for us both, and a bed for me. The first shuttle off this planet if you can possibly manage it."

"What?"

This was like pulling teeth. "You asked what you had to do. I'm giving you a list."

"Do not presume to—"

"Spare me the dramatics. Either give me

what I need to take care of Luke or kill me."

Vader fell silent, and the conflict roiled in him like a thunderhead under glass. Then he ground out, "Fine. But do not grow comfortable, Kenobi. You are here for Luke's sake and his only. The moment you cease to be of use to me, if you try to escape, if you do anything to make me question your care for my son, I will make you one with the Force."

Ben didn't bother answering as Vader swept from the room, long black cape snapping at his heels.

While Vader was gone, Ben weighed his options. He could take Luke and try to get back to the shuttle and vanish before the Sith could find them. It would be a close thing, but Ben has learned his lesson. No more staying in one place, no attachments. They would stay on the move and never rest long enough for Vader or the Empire to find them.

But neither of them had eaten in close to a day. And if Vader caught them…

Ben has no lightsaber and no destination. He certainly couldn't call on Bail, not with Vader at his heels. Alone, he would be fine. He had learned to be alone, to fade away, and if he left Luke, Vader might be content to let the Jedi go. But the thought of leaving the boy to be raised by a Sith in this evil-seeped castle made Ben physically ill…

No. He would not leave Luke.

He had sworn to watch over the boy. Though he couldn't have foreseen where such a promise would bring him, he would not break it now, not Luke needed him more than ever.

Despite his threats, Vader returned a short time later with a strange assemblage of supplies in a metal box: a container of something resembling milk, a few blankets, a set of black robes, some bandages, a few ration bars.

Wonderful.

While Luke sat wrapped in his cloak, Ben picked through the supplies. They would do, but it was clear Vader hadn't had a plan before he departed for Tatooine. Anakin had always said a foolproof plan was a failsafe plan. The memory hurt. Ben looked up. "And the crib?"

Vader pointed to the box. "It will do until I can build a replacement."

Did he expect to get a child to sleep in a metal- Sighing, Ben pinched the bridge of his nose. "It's better than nothing, I suppose."

"Excellent." Vader paused as if hearing something. He growled but turned on his heel. "See that he is fed and well-rested. I have other business to attend to, but I will return with a medical droid to assess his health in a few hours."

The doors hissed shut behind him, and the lock slid into place with an audible groan.

Ben sighed and laid a hand on Luke's head. "How did we get into this mess?"

Author's Notes:

Because I have no self-control, and because I think we're all starting to go stir crazy, have a free update! After this, I will probably go to an every-other-week update schedule so I can keep a few chapters ahead and continue to update my other AU.

It's not clear exactly how early the twins were born, but it's likely they were premature. Beru and Owen absolutely did their best, but Tatooine doesn't have a lot in the way of medical care, so Luke is very much a preemie Force sensitive, and his new home is not helping at all. As much as Vader hates Obi-Wan right now, he's more worried about Luke's well-being and not losing him.