Talking to Klaus felt a little like coming alive again, not that Barry personally had the experience. Like waking up, maybe, but it seemed like a long time since he'd felt this energised just starting the day. Like throwing the windows open. Like getting out of Mechanicsburg for the first time without their father, he thought wryly, and like coming home at the same time.

He'd been narrowly focused for so long - searching, fighting, trying to keep an eye on Bill, trying to keep Agatha safe, avoiding connections for fear of what might happen in his wake. Solving the problem currently breathing down his neck. Klaus had caught him off guard, reminding him that they had a lot more to worry about than that.

Barry... did not like the idea of forcing anybody to become part of something. It was wrong, it felt wrong, and moreover it struck him as asking for trouble. Like making somebody drink the Jägerdraught: if it worked, you got a tough, nearly immortal monster-soldier who was now mad at you. (This was actually not on the list of creative ways his relatives had found to kill themselves. Heterodynes were not big on common sense, historically, but they did avoid a few of the standard Sparky mistakes.) Or, say, coercing someone to marry you was not only evil but could get you poisoned by your wife. Just for example.

However, he'd never had a problem with the idea of hitting someone until they stopped causing trouble, even if he preferred to persuade with reason, words and example. He and Bill had still systematically avoided ruling anything except Mechanicsburg, either directly or through vassals - even if the people asked them to: partly out of personal distaste, which was still in play, and partly the keen awareness that as soon as they kept the lands of a defeated enemy, all of Europe would instantly conclude that was the reason they'd fought. Even then, they'd built defenses, negotiated treaties, arbitrated disputes, and set up communications to try to protect people who could govern themselves perfectly well but lacked the resources to fend off hostile neighbors or rampaging experiments.

Circumstances had changed. With so many of the Great Houses wiped out, there were even more leaderless threats than usual - even aside from the wasps - and a sudden surfeit of individuals and villages who'd lost whoever they normally appealed to for administrative or military support. It was no wonder a lot of them were turning to Klaus. And it was no more wonder that he considered himself responsible for people who'd been forced to attack him. The House of Wulfenbach had collected an astonishing variety of secondhand monsters over the years for basically the same reason. Klaus was remarkably good at finding place and purpose for thinking constructs who had been ill-used - one way or another - by their Spark. Sometimes before they'd even got around to confronting the Spark himself. Barry still vividly remembered the shock that first time - they'd faced off against a platoon of intelligent gorilla-frogs and he'd heard Klaus ask them if they actually wanted to fight. And they hadn't.

It mattered to Barry that he not rationalize treating other people badly just because he didn't want to fight his friend. But he didn't actually think Klaus would go that far - at least, not with someone to challenge him on the lines between necessary, expedient, and completely irrational. Pretty much every Spark needed that. And Barry could make a significant difference to what was actually feasible.

After about an hour of supposedly reviewing where the surviving governments actually were, they were in reality wandering onto tangents about things like road systems and Klaus's theories about schooling and how to make Spark breakthroughs more survivable.

"I was hoping for a more elegant solution to childrearing than a cage," Klaus said. "Anyway, given your talents as an escape artist, I wouldn't expect it to work on your family."

"It focuses the mind," Barry explained. "Why do you think we have three storage rooms full of lockpicks?"

"That was one of the many things I decided not to wonder about too-"

The door banged open to reveal Von Pinn, wide-eyed and white-lipped, entirely still but clearly not much calmer than when she'd hurled herself wailing first at the stone that had killed little Klaus and then at the nearest throat.

"What happened?" Klaus said, a note of command in his voice.

Von Pinn's gaze flicked between them. "Miss Agatha is gone. And Master Gil. I - I am sorry." She ended up looking at Barry, eyes wide and wild.

Agatha. And then, Not again. Barry felt as if his heart seized and stopped, but his thoughts sharpened and raced, twisting. He saw the color drain out of Klaus's face and his expression freeze - Gil was his, Barry was suddenly sure of it. Von Pinn was distraught but not fighting, which meant whoever had done it was out of reach. There had been no sign in the study of anything unusual going on. Distantly, he noted the thud of his next heartbeat. Only a change in subjective time, then. "What happened? We heard nothing."

"I was attending to some of the older children, and when I came back to check on Miss Agatha she was gone. I checked on the other children and Master Gil was gone as well. Nothing was disturbed."

Klaus took a deep breath. "We need to search the ship. They might simply have wandered off." His voice was steady, but he was pale enough Barry could see he was thinking of the other options. "Von Pinn, you stay here with the other children."

"Did any of them see anything?" Barry asked quickly. There was, he told himself, no conceivable way the Geisterdamen could have entered Castle Wulfenbach.

"No," said Von Pinn. "But no one was awake." She looked desperately unhappy about this.

"Ah. We'll find them," Barry said, telling himself as much as her. It had just better not take three years again. He followed Klaus out, listening, looking around. Trying to think where on a giant airship Agatha would want to go. What would interest her more than anything else. Under the circumstances she'd be a little spoilt for choice. "...They're being quiet. Is there anywhere Gil normally goes?"

"There's a place below the school he sometimes sneaks off to. I wouldn't have expected him to take Agatha, though," said Klaus. "We can start there."

Barry resisted his immediate impulse to vault the railing and figure out the rest from there. "Lead on, then."

The place under the school was a narrow catwalk, in deep shadow from the floor above it. Klaus ran his hand along a beam and came up with a book. "He was here," he said, sounding relieved. "Gil, at least, left the schoolroom of his own volition. It's likely both of them did."

Barry exhaled and looked at the book. Too dark to read it here, but probably the kid carried a lamp. "Agatha would probably have been too excited to sleep," he said. "So... kids. Yours, and Bill's..." A small, crooked smile. "Check the engines? And hope neither one got the notion to try taking them apart?"

"Probably the best place to start." Klaus shook his head and smiled back. "I suppose we can't complain. Maybe I should get Punch and Judy aboard, for their experience at getting us out of trouble."

"Not a bad idea, but it would take a while." Barry started toward the thrum of the engines, not actually that far off, dropping to a lower catwalk after several steps. "They moved to Beetleburg a few years ago."

Klaus dropped to the catwalk after him, making it judder. "That would explain why I couldn't find them when I returned."

"Haven't been back to visit the university?" They were moving quickly, because small children and big engines were not the best combination and intelligence - especially that of prospective Sparks - might merely mean a different kind of bad combination. But much of the initial horror had faded with Klaus's certainty that Gil left on his own. "I don't suppose you've had time. Even as fast as you work, you can't have arrived all that long after we left."

Klaus grimaced. "Almost at the same time, I think. Which has done nothing to help the rumours."

Barry rolled his eyes, from about the level of Klaus's feet as he started down the scaffolding at the end of the catwalk. "No, I imagine it wouldn't. That at least, I can fix."

"If only by being helpfully alive," Klaus said, following him down.

"Oh, I can do better than that." Barry gave Klaus room to get around him to the engine room's door, but when opened, it revealed only engines. Very nice engines, and with no evidence of blood or screaming, but also no evidence of children.

Not present children. Something caught the edge of his attention; he paced a few steps, then leaned down and picked a fine red-gold hair from where it had caught against the wall.

"...I suppose we now know our children are smart enough not to tamper with the engines of an airship they are currently on. Which is better than we've done in the past," said Klaus. He rubbed his head. "Gil must have been showing her around - he's been wandering much farther than I realised if so. Where would he take a child he was trying to impress?" He looked at Barry. "Any idea what Agatha would be impressed by?"

"The entire ship," Barry said, aware that this was complimentary but unhelpful. "A lab?"

"The closest lab would be..." Klaus paused to recall the layout of the ship. "Unfinished, actually. But we might as well start with it. This way."

"That might be a good sign. Things in progress are always interesting."

"Let's hope so."

Indeed. So far the evidence was encouraging but not exactly a guarantee of safety. Barry followed, thinking he really hoped both children were as surefooted as they believed themselves to be, and then paused and caught Klaus's arm to stop him. "Do you hear that?" Something faint, distinct from the noise of the ship itself.

"Yes," said Klaus doubtfully. "Is that music?"

Barry debated that for a moment. "It's musical notes," he said. The notes went up, skipped, then back down and steadily up again at semitone intervals. "It's a chromatic scale." He reached overhead and plucked a heavy wire cable, making it buzz briefly. "Played on electrical wiring." A sudden grin. "I think they're all right."

Klaus closed his eyes for a moment, looking limp with relief, and then returned Barry's grin. "Time to go and find out what they've made."

"And add music lessons to your curriculum," Barry suggested.

"I don't know if Von Pinn is particularly musical," Klaus said, sounding amused by the thought.

"She can play the harp, but she doesn't like it much. You'll need more teachers eventually anyway. We could always ask Lilith." At Klaus's mystified look, Barry clarified, "Judy. They wanted a little anonymity." Beetleburg was perhaps not the most obvious place to seek it, but Dr. Beetle accepted their wishes and much of the population was only there for a few years at a time. "So she might say no," he added, "but now that I'm not trying to hide Agatha, I should write to them, anyway."

"That's not a bad idea, if she is willing. I'd like to see them again, anyway," Klaus said. "Here we are," he added, unnecessarily, as they came to a door from behind which the chromatic scales could still be heard. He pushed it open.

They had certainly made themselves at home. Agatha was sitting cross-legged on the lone worktable. A boy only a few years older, with wild brown hair, was using a crate as a stool. A large tool box, a variety of wires and gears, and possibly some pieces of the wall paneling were on the table with Agatha, and much of the material had gone into a partial box they were both leaning into, containing a system of wires clamped taut at different lengths from a metal bar.

Both children looked up at the sound of the door. Gil shrank back against the table, eyeing them warily from behind his mop of hair. Agatha launched herself off the tabletop and ran to Barry, beaming. "Uncle Barry! Baron Wulfenbach! I met a new friend, he's Gil Holzfäller, come and see what we're making!"

Barry caught Agatha up reflexively, then paused, looking at Gil - Holzfäller? - and then inquiringly at Klaus before striding over to the table and setting Agatha back on it. "Hi, Gil. I'm Barry Heterodyne. You had us a little worried, but I'm glad to see you're all right."

"Hi," mumbled Gil, looking up at him.

Barry smiled at him, which Gil appeared to consider another overwhelming aspect of the situation, and then turned seriously to Agatha. "I really am very glad to see you're all right," he told her. "There are people who'd like to take you away and hurt you, and I was afraid at first some of them could have done it. Or that you'd be injured climbing around here. It scared Madame Von Pinn pretty badly not to be able to find you, too."

Agatha squirmed a little. "We didn't do anything dangerous."

"You were in the engine room," Klaus said. "Gil, you know it is forbidden to leave the school. Much less take a younger student into places like that."

"We didn't touch the engines," Agatha argued.

"Sorry," said Gil. "...is Madame Von Pinn all right?"

Barry looked at Gil. "She's... distressed. She lost the first little boy she was supposed to be taking care of, through no fault of her own, and I think we'd better go ahead and tell her we've found you both."

Klaus picked up the box from the table and tucked it under his arm. "Yes. I think we'd all better return to the school."

Gil nodded, looking stricken. "I didn't mean to upset her. I thought I'd be back before she noticed."

Agatha, too, had wilted a little at this information. Barry caught her as she tried to jump from the table again, and they began the walk back. She didn't argue about being able to walk this time, but she did start peering down from his arms again. "I didn't think the walkways were big enough for you," she remarked.

Barry tried desperately not to laugh and had to clear his throat before he could speak. "We have a lot of practice."

They returned to the school, two rather chastened children in tow, to find the rest of the students awake and, not unreasonably, treating Von Pinn with kid gloves. Agatha, on the other hand, rushed up to her and said she was very sorry to have upset her but she'd gone looking for secret passages and nobody had been in any danger. (Barry considered disputing this last point but decided it wasn't worthwhile.)

Then Agatha hugged her, and Von Pinn froze, both clawed hands poised as if she had no idea what to do with them, before gingerly lowering them and patting Agatha on the shoulder. "Child, you must-" She paused, then looked up and met Barry's eyes. "Will she be enrolled in the school?"

Agatha let her go and whirled around. "Will I? I know most of the students said they're hostages, but I think it would be really fun!"

"It's not actually meant to be an unpleasant experience," said Klaus drily.

Several of the students looked various shades of embarrassed or alarmed. Barry noted one boy with a distinct resemblance to the Iron Sheik, an old friend and not a particularly near neighbour, so there was at least one student there - probably - for the education, academic and otherwise, and as diplomatic support. He arched an eyebrow at Klaus. "We may have to have a talk about these matriculation policies," he said, straight-faced, "but I'm sure Agatha would be quite safe here." He crouched down to meet her eyes. He was reluctant to let her out of his sight, especially so young and having been among the Geisterdamen, but he'd seen she was craving the company of other children, even before the light in her eyes now. "But I can't send you here if you're just going to ignore the rules."

"It was Holzfäller," blurted one of the students. "He's always trouble."

"I followed him all my own self," Agatha snapped, rounding on her. She turned back to Barry, frowning. "Do I have to say I'm sorry, to come?"

Barry put his eyebrows up again. "Are you sorry?"

Agatha huffed. "I'm sorry I upset Madame Von Pinn and worried you," she said, but then added frankly, "but not that I followed Gil. I didn't get to talk to him much before that and it was a lot of fun."

Barry lowered his head for a moment, fighting a smile. He couldn't quite blame her for that. "I appreciate the honesty," he said, "and I'm glad you're making friends, and I'm very glad you were careful. But you're still going to have to understand and follow the rules if you're going to go to school here. The people taking care of you need to know where you are so we can keep you safe. If you disappear, we can't just assume you're okay and leave it at that." He shot Klaus a wry look. "It's pretty worrying when grown-ups do it, too."

"Indeed it is," Klaus said, just as drily.

Agatha considered this. "So if we say where we're going, can we go?"

"Not necessarily. You have to ask."

Barry was expecting further argument on this point, but Agatha looked up at Klaus and asked instead, "Is Baron Wulfenbach keeping our music box?"

"Well," Barry said reasonably, "you did make it out of his things, didn't you?"

"How about a bargain," Klaus suggested, bending down to meet Agatha's eyes. "You and Gil can have it back to finish, if I get to look at it once you're done."

"Yay!" - which presumably meant yes, and Barry ducked his head and did chuckle at that. He looked up in time to catch Agatha looking suddenly uncertain. "I'm not sure the sound quality's ever going to be very good though," she said reluctantly.

"Considering that material was meant for building a laboratory I'm impressed you got recognisable notes," said Klaus. "If I'd known you were going to build a music box I'd have provided better materials."

"Does that mean we can have materials to build things?" Theo asked, looking hopeful.

"If you can all manage a little patience I'll provide a teaching lab," Klaus told him.

"That means you should probably avoid taking it apart while he's trying to build it," Barry threw in.

Agatha was beaming by this point. "You are nice," she said, and flung her arms around Klaus's neck while he was still in range.

Klaus stiffened and threw Barry a 'what do I do now?' look, before patting her back carefully.

Barry didn't think that was quite it, so he went over, scooped Agatha up in one arm so Klaus could straighten, and slung his other arm around Klaus's shoulders. He restrained the impulse to actually hand Agatha to him just to see the look on everyone's face. "I've always liked him, myself."

Gil watched Agatha, looking a little awed, as Klaus gave in to the proximity and awkwardly hugged her back.

Barry seriously considered trying to come up with an excuse to grab Gil too, but couldn't think of one. Agatha squirmed at that point, so that Barry rather hastily let her down, and she darted over to hug Gil around the waist. "We get to finish the music box," she informed him, gleefully and completely unnecessarily.

Gil shot some of the other students a wary look, as if he expected them to somehow take the music box - or possibly Agatha - away from him before it could happen, and then gave in and smiled. "Yes," he said, hugging back.

"If all of you can try to stay put for now," Barry said, "Klaus and I have a few more things to discuss. Agatha, we'll be going back to Mechanicsburg for tonight, but I'll plan on enrolling you here." A raised eyebrow. "If you think you can behave."

Agatha smiled at him. "Yes, Uncle Barry."

Klaus set the music box down and asked Von Pinn to get them some tools so they could stay "busy and out of trouble" for a while, before following Barry back across the hall and into his study.

"So," Barry said, once they were in private again, "obviously you decided to keep Gil anonymous." But Gil's own reactions... Slowly, he added, "But just how bad is the amnesia?"

"Worse than I realised at first," Klaus said. "He doesn't remember Skifander at all. Which might be just as well... At least he isn't missing his sister." Klaus sighed. "He's aware he was the first of the children to be here, he remembers travelling with me vaguely, but he also knows some of the other students are orphans I picked up."

Barry tried to imagine having that much missing, and whether even at seven, it would be possible to avoid realising something was terribly wrong. He failed. After a long look at Klaus, he said, "And you haven't told him he's yours, either."

"The less people know the more chance it has of remaining a secret," Klaus answered.

Barry rubbed his forehead. "Possibly true," he conceded, "but you're keeping even more of his past from him than he actually lost. And if he doesn't miss you, anyway, I'll be astonished."

"He hasn't shown any sign of expecting a closer relationship with me than I have with any of the other students. I think if he really remembered..."

"He's seven," Barry said quietly. "You're in charge of his entire world, and you've told him his name is Holzfäller and not treated him like you expect a closer relationship. Haven't you?" He shook his head. "That could make somebody doubt a lot more solid memories than it sounds like he's got." He wondered sometimes if he was telling Agatha too much of the truth or not enough, and he often hoped she'd just forget the Geisterdamen with time and the changed world. She still seemed to remember all too well, but with no reminders, maybe...

"I want to keep him safe. Being confused won't kill him. Being known as my son might," said Klaus firmly.

Barry opened his mouth, thought, He already lost him once, and shut it to let out a long sigh through his nose instead of speaking. "I don't blame you for worrying," he said quietly. "But I still think you'd both be better off if he knew."

Klaus shook his head. "I'll consider it. But if I tell him I won't be able to take it back, and it's not something to do in haste."

And relying on a seven-year-old who'd just decided to give a new-met friend a tour of the ship to keep secrets was perhaps not exactly reassuring. Barry grimaced. It still didn't feel right, but he wasn't sure what he'd do in Klaus's place. "Are you having a lot of trouble with assassins?"

"Less so now I've got hostages from some of the families that were trying it the most. But yes," said Klaus. "I'm not sure whether you joining me will cut down on that or lead to people trying to assassinate you. Sorry if it's the latter. I'm hoping it's the former."

"So do I," Barry said, "but I'll manage either way."

Klaus smiled. "I know you will."