Which they are. Sadde's suggestion that they try focusing on shorter parts of memories for a higher happiness-per-second value helps him but not Miranda, so he ends up with a more solid fog. Still just fog, though. They continue reading books about it, and it seems to just be that idiosyncratic. Interestingly enough, some books written by alchemists also have mentions of Dementors, trying to figure out what their symbolic value is and whether it's possible to integrate it. More advanced books are in the Restricted Section, and they won't have access to it until at least Professor Slughorn gives them the go ahead.
The year passes. Willow is consistently good at the theoretical parts of classes and consistently bad at the practical ones, mostly due to being flustered by failures and not quite being able to get over that fact. Sadde and Miranda are exceptional at Potions, and the only reason Sadde isn't also exceptional at Transfiguration is that he doesn't quite care enough about homework when all that's on the line are his grades. That, plus all the time he spends between reading about Dementors, reading about Alchemy, and trying to undo the damage suffered by Slytherins because of the Dark Lord.
That last goal has the most tangible results, for a certain value of "tangible." Slytherin firsties are divided between liking him (Jacob and two of the girls) and grudgingly tolerating him (the other boy and girl). He has thoroughly dispelled the notion that he's "just another Slytherin" firsties from other Houses (except perhaps Gryffindor) might have, but of course that doesn't make the older years all that happy. Well, not that the older Slytherins actually care that much. But he has helped various of them with various things, mostly by acting like a somewhat willful minion, since there's not much more he can do to help older students beyond that, so he's at least on talking terms with most of them (Cole and Astoria have been quite useful there, as well).
Arens is not one of them, but by now he's mostly just ignoring Sadde and hoping he'll just go away.
Summer arrives.
They return home and spend a while with their respective families, but eventually...
"It's because it's actually really hard to do it right, if you swing too hard you overshoot the target, but not hard enough and you don't quite reach it, and the hole is only big enough for the ball to fit so you have to be really precise. ...it's not actually much fun as a team sport though I just suggested it because we have a mini-golf course."
"I kinda want to go swimming," says Karen. "After seeing the house. If I'm picking, I mean."
Karen is very alarmed to discover that they have a human, Muggle cook who is not part of Willow's immediate family.
"Nice to meet you, loves. Would you like me to make you something?"
She looks at the other three, but pretty meaningfully at Karen, and says, "It's okay, you can ask for whatever you like and there won't be any problems."
...Miranda stands near Karen and tries to look related to her or something. "We're not hungry but thank you."
And Willow promptly ushers them out.
"Sorry, er, I forgot about her!"
"Sorry! There aren't any more—well except for Mr. Boris who minds the horses but I can get him to go away before we go play with them."
"It's okay," says Miranda. "You didn't say anything to her. Just tell them you didn't talk to any Muggles who weren't in under the Statute."
"For breaking the Statute of Secrecy. If I said the wrong thing. They said when I'm older I could try going somewhere as long as people who know about Muggle things are with me but for now they don't want to risk it."
"They might not be assessing the risk quite right but it would have been pretty easy to ask Ms. Hannah for pumpkin juice, say, and she's probably already wondering why Karen is dressed like that." (Karen lacks Muggle street clothes; what she has on is not a school uniform, but it would barely be in-place at a renaissance faire, let alone out and about in a Muggle town.) "The risk is much worse for Ms. Hannah than for Karen, whyever her parents made the rule, anyway."
"I don't think she's wondering about that, my brother's brought people dressed, erm, differently before, and both mum and dad have varied guests—okay, I'm making up excuses, sorry, I just didn't think of it."
"Nothing happened. But maybe Karen shouldn't come over again anytime soon unless Ms. Hannah's having a vacation."
She nods. "Well, erm, want to see the rest of the house? No other muggles here." Pause. "Except for mum and siblings but they know."
There are at least three rooms that could be reasonably called "living room," and there's the dining room there, and the games room, which has a chess table and a checkers table and a backgammon table and a go table and a few other scattered tables and chairs and a little couch and decks of cards.
"See anything you like here?"