Disclaimer: I do not own Howl's Moving Castle, though I would be ecstatic if I did. Here's what I made up so far: the intruder (Kyria)
Howl closed his door quietly. Sophie, who was lying on the bed, asked, "Is Markl asleep?" The wizard nodded, "Yes, and so is Calcifer. And the Witch of the Waste." He came and lay down beside her. His restored heart beat steadily, the rhythm mixing with Sophie's.

They heard the creak of the floor downstairs. Howl shot to his feet, "That's not Markl. He's still in his room. And the Witch can't move that fast." Sophie got up and stood beside him.

The wizard opened the door and crept out. The pair snuck past Markl's room and down the stairs. There was no one to be seen, except for Calcifer. The fire demon was slumbering peacefully.

Howl looked all around the room, searching for the maker of the noise. Sophie helped as best she could.

Suddenly, a hand clamped over her mouth and something cold and hard pricked her neck.

"Make a sound and I'll slit your throat."

Howl continued poking into the corners of the room until Sophie's captor finally spoke again.

"Howl," they called in a singsong voice. The wizard spun around and gasped. He started towards them.

"Come any closer and I'll kill her. You know I will."

Howl froze, eyes gazing sadly at Sophie. She shook her head slightly, trying to make him go, make him save himself. The wizard did not move, just stared at her.

Sophie's captor warned him, "Don't move a muscle or she's gone."

Howl hesitated, then nodded and stood stock still. The intruder snapped her fingers. Sophie gasped as ropes sprang up out of the shadows and slithered, snakelike, across the floor to the motionless wizard.

They wound themselves around his arms and legs until he could not move, even if he had wanted to. Howl swayed for a moment, then fell with a thud. There was great sorrow in his eyes.

Sophie's captor neatly tripped her and pinned her down. Ropes appeared out of nowhere and Sophie soon could not move any more than Howl.

The wizard's deep blue eyes flashed in anger, "Leave her alone! She has nothing to do with it!"

The intruder stood up, "Everyone has something to do with it if they're around you, Howl."

Sophie managed to roll over and saw that a woman stood over her. The intruder's long golden hair shone slightly even in the dim firelight. There was something slightly inhuman about the slenderness of the body, but Sophie had no more time to think about that.

Howl struggled to a sitting position and glowered, "I said, leave her alone! She has done nothing to deserve this!" The intruder laughed and gestured. A strip of cloth slithered over and gagged the wizard. He continued to struggle, though now silently.

Sophie gaped at her captor. "You're a witch!" she exclaimed. The woman simply bent over and gave her a sharp tap on the head. Sophie went limp.

Howl struggled even harder, glaring daggers at the intruder. She smiled, "Don't worry, Howl. I do not unnecessarily kill innocents. She is simply knocked out."

When the wizard continued wriggling, his captor sighed, "You may as well stop. Nothing you try is going to loosen those ropes. They are made of pure magic, of a sort you could never hope to break. I give you my word that she will not be treated badly. You know I never break promises."

Howl relaxed as much as his bonds would allow, and nodded.

She picked up Sophie's limp form and slung it over her shoulder. With a wave of her hand, Howl floated up into the air.

The intruder summoned up a little note for Calcifer, the Witch, and Markl. She placed it near the hearth, then headed out the door.

Howl involuntarily floated out after her. He watched, unsurprised, as huge, pure white feathery wings burst from the woman's shoulder blades. She soared up into the air, and the wizard had no choice but to follow.

I wonder where we're going, Howl mused, her old lair burned down ten years ago… They soared through the night sky, leaving no trace that they had ever been there.