Help, help, says the castle to the void. This is not usually a good idea because the void is not incredible at suggesting things that won't, like, explode on contact with normal physics, but look, this is important. My children. Something is wrong with them. 

o̶o̵o̵h̵! ̸i̸m̴ ̵h̷e̷l̸p̵!̶ ̷i̴m̵ ̶f̷o̴r̷ ̸h̴e̶l̸p̴i̶n̵g̷.̴ ̷c̴a̸n̵ ̵u̸ ̴b̴e̴ ̵m̷o̷r̵e̷ ̵s̵p̶e̴c̸i̶f̴i̵f̵i̴c̵.̷ ̵

Um. They are about to all start killing each other because they are all very scared and not doing a good job thinking about why or whose fault it is, I think. 

y̴i̸k̸e̷s̵.̴ ̷h̵m̸.̸ ̴h̸m̸m̸m̷m̶.̵ ̴I̶ ̷a̴m̸ ̴h̴a̸v̴i̴n̵g̵:̷ ̷a̵ ̶g̸r̵e̶a̶t̸ ̵i̵d̷e̵a̸!̴ ̶I̴ ̸g̸i̶v̶e̶ ̷y̴o̶u̴:̴ ̸a̶n̸ ̸f̴r̴i̴e̷n̸d̸!̶!̵ ̸m̷a̶n̶d̷a̵t̴o̶r̷y̵ ̶b̵e̴ ̷n̶i̵c̸e̶ ̶2̵ ̸h̵e̶r̷ ̷o̸r̸ ̴e̷l̷s̵e̸.̸ ̵s̶h̸e̸s̸ ̵e̸v̵e̷n̸ ̸w̴o̷r̵s̵e̸ ̴@̶ ̸h̴u̶m̵a̶n̸ ̸w̸o̴r̵d̵t̴h̸i̴n̵g̶s̶ ̴t̶h̶a̵n̷ ̶m̶e̷

Hogwarts is not sure this was a good idea even in this case but it is Too Late. What on Earth or otherwise has she just been handed. 

Something small and slight slips sideways into a space that mostly isn't, and starts singing there.

The song is about bittersweet nostalgia for a time that wasn't very good but is still worth remembering. Her many voices croon and shriek and chime and whistle, weaving chords that only mostly fall within traditional human hearing range.

Oh. 

...

[the number of Children of Hogwarts has been incremented by 1]

...

Most of the inhabitants of Hogwarts cannot hear this very well. (This is not really a matter of their location in the castle, or the quality of their ears, or the acoustics; it's just that the castle doesn't force things upon you that aren't right for you.) But--

Some of them have a lot of history that wasn't very good. 

🎶

It wasn't a good place to be, but you were there. It wasn't a nice way to live, but you lived it. And maybe once in a while you felt the breeze, or saw a tree, or read a book, or smiled. Maybe once in a while, just for a moment, something was okay.

🎶

and the world was smaller and fewer things were his fault, which in retrospect was nice.

Ah. His roommate is looking at him funny. Damn observant for a teenager, that one. Well, now that he's finally figured out how to lie to the Quill about his birthday (look, having to repeatedly pretend to be an immigrant in his own damn country because nobody remembers him going to Hogwarts was the worst, okay), maybe his next exhausting multicentury fraud project should be the bloody Hat. "What?"

"You hear something?"

"Uh. Might be imagining it. You know any auditory enhancement charms?" 

At least three because he is the most brilliant human alive and is going to rule the world, yes. 

He's so helpful. Hob really has no idea what Professor Dumbledore's problem with him is. 

Does the song sound different with a wider range of hearing? This spell is for diagnosing injured trees, this is apparently useful in NEWT Herbology (which he's not taking until Herbert Beery isn't teaching it, the man will not shut up about theater), but the way you do that is you listen to them, you see. 

Heard across the full range of its haunting notes, the song has more emotional depth, more literal and metaphorical resonance. It tells a stronger story, winding through the long sad sprawl of memory and ending on a slow, reflective progression as the inhuman chorus sings with quiet sadness and warm hope of the transition from what was then into what is now.

Oh. Yeah. That is the whole point of him, isn't it, the that-was-then-and-this-is-now. For new nows, forever. There might be several wars but we'll feel like this about that, someday. Thanks, castle, love you too. 

... 

Ah, shit, he's crying now. That's... not really best advised in Slytherin House, even when there's not many other people about. He blinks rapidly and hopes it's not too obvious. Tom is still watching him with rapt fascination-- he's always like that about magic he doesn't yet fully understand, it's a wonder he's not a Ravenclaw, though Ravenclaws are usually much worse at making friends, so maybe not that much of a wonder-- but with any luck he'll be much more interested in a lively academic speculation than in Hob's feelings about it. 

"Can you really not hear that at all? Castle's singing. I don't think it usually does that?" 

Tom's eyes light up. "Well, technically speaking, the atomic spellform 'song', which you see in radio enchantments, bird conjuring, animated violins, analytics of veela magic, and the like, is exactly what the Hogwarts morning alarm uses. That's why it's so oddly pleasant. Why's it singing specifically to you?"  

Hogwarts you disloyal idiot! Tom loves you more than anybody!! ...can't show that on your face, good god. Chill friendly teasing smile. He is so normal. 

(Hogwarts can feel it, a little, when her children love her. It's a bit like having a cat purr very quietly while you're holding it. This is very good. The current heir of Slytherin metaphorically purring at you is also a bit like being set on fire, though, which is not ideal.

The singer in the walls can ~hear the castle perseverating anxiously about her metaphorically flammable children but this may or may not mean she can understand; castles do not use language the way humans do but Hogwarts is still in most ways more like a human than like a void creature, probably.)

She does hear something, in an odd distant garbled sort of way; and she thinks for a little time, and then sings a different song.

It's about being someone who needed protecting, and not being protected; being, in fact, so unprotected that it seemed sometimes like no one was even trying at all. But that wasn't true. People were trying, and it's good that they were trying. She's glad they tried, even though they failed. It was a pretty impossible job.

Ah. Distraction magnitude nearly zero, alas. "Seems like it noticed I was thinking too much about the war instead of doing my homework," he says, trying for lightly dismissive and mostly hitting it. "Probably you've never heard it do that because you always do your homework."

Tom stopped listening halfway through that sentence and is staring at the wall, eyebrows furrowed. 

After a moment, he says, flabbergasted, "How dare you??"

"Uhhhh sorry for.... implying you're... a good student??" 

"Not you," he snaps, impatiently. Hogwarts what the hell is this!! What do you mean it was good they were trying. First of all no they weren't and second of all trying and failing counts for exactly nothing. This is some foolish Hufflepuff bullshit trying to trick him into accepting the status quo and he is Not having it. 

Oh that is a teenager feeling defensive. Hob resists, narrowly, the urge to begin his next sentence with look, kiddo. "Normally you're the last person I'd think ever needs advice from anybody but Hogwarts is about fifty times older than us," you, "'and the thing it said to me was really useful even though it kind of stung. Listening with your nifty tree spell helped." 

...

...

yes, all right, more information is never worse. what do the castle's blatant lies about the value of pointless effort sound like in tree hearing. 

what was that about how no one was there for him and that sucked and someone should have cared. can he hear more about that actually. 

shut up, brain, we're not five. 

🎶

It was very hard, being small and scared and not having anyone to turn to. It was so hard that she gave up, and decided that no help was coming and she needed to make her own way out of the situation. She doesn't regret it but that doesn't mean it was good that it happened; it would be better if, instead, someone had been able to protect her. But protecting her was very hard, too. She can see that, now, looking back. She is glad they tried, instead of giving up entirely. It feels better, remembering it, to know that her small scared self wasn't as alone as she thought she was. There were people who wanted her to be okay. She wants herself to be okay; and it's good that she does, even though she can't reach into the past to protect herself.

🎶