That summer is literally the best of Harry's entire life so far.
Vernon nearly exploded with rage when they showed up with all their luggage and Hedwig - and Bloom.
But she said she was a friend of his and wouldn't be a problem - and he grudgingly let her stay when Harry said she's got nowhere else to go.
To prove her point about not being a burden, she made an apple in her hand out of magic and bit into it.
Dudley stares in shock, and asks "Potter how the heck did you meet this girl?"
"We met at the train station Dudley, then we took the train together to school."
Vernon says "Well, you won't be using any of those powers of yours around here you two. We received a pamphlet explaining how you people aren't allowed to use magic where normal people could see and find you out."
Bloom swallows the last of her apple, snaps her fingers and makes the core vanish, and says "Actually, that's just for Harry. I'm not technically a witch - not part of this Wizarding community."
To prove her point, she makes a fireball in her hand and snuffs it a second later.
"So, those rules don't really apply to me - at least, not for my fairy powers. So, I'm afraid there'll be some magic going on - whether you like it or not."
She glares at each of them in turn, matching even Vernon's glare perfectly.
After a moment, Vernon says "If you embarrass this family-"
"Oh please, the human world isn't ready for magic. Nobody outside this house will see so much as a sparkle off my hands Dursley. Come on Harry, let's get unpacked."
Harry grabs Hedwig's cage, and Bloom floats all their stuff up the stairs as they walk up.
Her thick-as-heck book that she got for Christmas is actually a spellbook from Alfea - she got a wave of magic from it from all her friends from Alfea, and inside are the spells she would be learning at Alfea.
She's gotten through all of them in record time, making up a whole year in half the time along with classes at Hogwarts.
She and Harry have to share the same room - but that's fine by both of them.
Bloom makes a bunk bed appear on top of Harry's, and they get their stuff sorted out fast.
Bloom floats their clothes into the closet, while Harry gets their school stuff out.
"Thanks Bloom, really. You have no idea how much this means to me. You staying with me here, keeping the Dursleys off my back. I thought Vernon would have a heart attack when you said your powers are different."
"Well, they are different. I'm from another universe entirely, and that universe just expects us to use our judgement on using our magic."
"Yeah, how'd you get your wings though? You never had them before. Or is that how you beat the troll?"
"No, it's not. I really did break its club over its head - I just used my fairy magic for that. I earned my Charmix by saving you, you're my friend after all."
"And, what happened to Quirrell and You-Know-Who?"
Bloom shrugs, completely at a loss for explanations there.
"Controlling fire?"
"That's something most people can't do. I can because I have the Dragon Flame and because I worked so hard at it. It's one of the powers the Dragon Flame gives me - along with turning this soft or melting them completely."
"What? Nobody ever saw you-"
"I did it at night, when everybody else was sleeping. That way, I wouldn't be the freak of the school without some power to back that up. Turns out it was a good thing I spent so long in front of that fireplace though. I wanted to learn to control the 'immense power' inside me, and now I can. At least, a little. This thing is so much bigger than me, I don't know if it can really be truly controlled."
Bloom looks at the floor sadly, and Harry says "Sure it can. You worked all year long in secret to learn to control it, I'm sure you can do it."
Bloom smiles and says "Yeah, your right. Besides, I bet Snake-face didn't know what hit him in the dungeons."
They both grin, imagining a ridiculous look on Voldemort's face for a moment.
Harry sighs when they get unpacked, and says "About meals…"
Bloom says "You said. They make you cook everything for them and you only get scraps. Well, I'll be happy to share Harry."
She concentrates, and suddenly about five plates are floating in the air filled with their favorite foods from Hogwarts.
Harry asks "How much did you learn at Alfea?"
"Not a whole year's worth, but this spell was in the book they sent. It's fairly easy, so we'll have instant food whenever."
Harry breaks out into the biggest grin he can remember having in a mile of his blood family.
"Bloom, you are bloody well amazing."
"Thanks. But there's a side to my magic that can be pretty scary, Harry. If I get too mad and lose my grip on my powers, things blow up. If I get scared, really scared, any fire in the area reacts and is called to me. And if the Dragon Flame comes to the surface, well, stuff happens. My eyes turn orange, all fire in the area leaps feet higher, and I'm told my skin catches fire - I never feel a thing except for fire in my veins that doesn't hurt and my magic covering every inch of my skin."
They eat everything on the plates, and make them all disappear with a snap of Bloom's fingers.
Harry grins and says "How long do you think it'll take them to figure out we aren't going to go hungry?"
Bloom whispers "Not long, we won't be getting skinny!"
Suddenly, they hear a rapid knocking on the door and Dudley shouts "Hey, what are you two doing in there?"
Harry says "Unpacking, cousin. We brought more than a few things."
Dudley barges in, and immediately says "I smell food. What'd you guys bring?"
"Nothing, there's no time to take anything from the hall before we pack."
"Well, I smell fresh food in here."
Harry rolls his eyes, Dudley's always thinking of his stomach.
Bloom says "Well, ask your mother for a snack. As you can see, we only have clothes and supplies in here."
Dudely sees her wand and bends down to get a closer look.
"DON'T TOUCH IT!" Dudley jumps a foot in the air at her sudden shout, and looks around warily.
"What?"
"The last kid that waved my wand ended up flat on his back and covered in soot! I seriously doubt your parents would be very happy if you came down after an explosion looking like that - he was also very sore, and could hardly sit up at first."
Dudley backs away from the wand, just as Vernon knocks on the door.
"What's going on up here? Why all the shouting?"
Dudley yells "She's got a killer wand!"
Bloom rolls her eyes as Vernon slams the door open.
"What?"
"A person's wand violently reacts when another waves it, and Dudley looked like he was going to pick it up. I didn't want the room getting torn apart, that's all. I also didn't want him covered in soot and extremely sore - which is exactly what happened to the last kid that waved it as a joke."
Vernon glares at her, which she meets evenly.
"Well, next time I'll let your son try to get himself killed by waving a magical instrument around and destroying a room in that single motion."
"If your magic is different from Harry's…"
"I can use the wand, and I have to at Hogwarts, but I don't strictly have to in order to use my magic."
She demonstrates by floating the wand over to a drawer, opening it, putting the wand in, and closing the drawer without moving a muscle.
She feels a wave of pride from Harry - they sort of accidentally connected when they faced Voldemort together, and the bond is strong.
She can feel his emotions if they're strong enough, and vice versa - and they can share magical strength, if need be.
Vernon's face turns purple however, and he looks like he's about to burst a blood vessel.
"I won't have any of that funny business in this household!"
Now Harry feels a wave of anger from Bloom - and then he feels something else inside of her start boiling up, it has to be her magic.
"Magic isn't 'funny business' to people who have to control it at all times."
Harry can tell she's trying to keep her powers from lashing out, but given the fact that she has a passionate disposition - something's bound to go up in flames at some point.
"Oh really? Control it how? Not wave your fancy stick around?"
Vernon suddenly takes a large step back from Bloom and Dudley all but shrieks in terror.
Harry moves to look, then discovers the reason why his uncle and cousin are so afraid, Bloom's eyes are turning orange!
"No, not a lack of wand-waving. I mean keeping something from blowing up or catching fire suddenly."
Bloom puts a hand to her head and starts rubbing her temples and trying to keep her magic from exploding and burning the entire house down.
Vernon backs out of the room fast, and Bloom and Harry stay upstairs for the rest of the day.
The Dursley's keep far away from Bloom - so they have to keep away from Harry as well, because they stick together like they're glued together.
Bloom and Harry practice magic in their room - after Bloom managed to magic-proof the walls and floor, along with sound-proof - and they basically spend the entire summer in that room when the Dursleys don't take them somewhere.
If the three humans don't have to go near the room Bloom and Harry are sharing - they're sharing it because Bloom insisted he wasn't going to spend all summer in a broom closet - then they go nowhere near it after Bloom's near loss of control.
All-in-all Harry has the best time he's ever had with his remaining blood family that summer - they leave him alone and do their own chores thanks to Bloom's presence.
When Bloom asks if he wants her to come back next summer, he immediately agrees, nearly begging her to, actually - and hugs her heard enough to squeeze the air out of her.
AN: For everyone that thought there'd be the rest of the Winx joining, sorry. There's too many things they'd need to get past - Sorting, wand-usage instead of their own powers, etc. Bloom was chosen alone because she wasn't nearly as used to using her fairy magic as everyone else in the entire school - it helps with blending in - along with the fact that she's the Holder of the Dragon Flame. The rest of the Winx grew up casting spells from their fingertips, something year six students at the earliest are able to do. And, if the mission wasn't gossiped about over breakfast one day, they'd somehow have to coordinate their plans without people finding out. Phones are the obvious choice, except Witches and Wizards in this world don't use technology as their powers short it all out. Also, Bloom really wasn't going to let Harry stay in a broom closet for a single instant - not while she's around. She just made a second bed appear at the other side of the room.