I stare. I'd known where this conversation was leading to, I suppose, but it it's still a shock to hear. At least I now have a name for what I have. Or what I am, apparently.

Omega.

I can work with that, I think.

"And what makes them different?" I ask.

That's where everybody appears stumped or uncomfortable. Lavender giggles. Harry shrugs. Ron has a little crease in his forehead like he gets when he's asked to answer anything in class.

"They're just... different," says Cetus hesitatingly. He's slowly turning red. "I don't want to say how. But they are."

Cedric Diggory's head breaks through the surface of the lake. We all stand automatically and applaud. He makes his way slowly to shore, dragging Cho Chang with him; her long hair floating like seaweed in the water.

"There's a doomed romance there," Lavender snickers.

"You should probably talk to her." Rohesia leans down to speak in my ear as we watch Diggory wrapping the shivering girl in a thick towel. "She's the only Omega outside of Slytherin. Besides you of course."

The stands begin slowly emptying of people. After over an hour of sitting and staring at the lake, very few are interested in waiting for the judges' scoring, all confident that Diggory would receive high marks. Fleur Delacour hadn't even managed to rescue her sister.

"What sort of Champion gets trapped by Grindylows?" says Cetus scornfully. "I actually feel embarrassed for her."

The train compartment is overly crowded. There are ten of us in here, not counting six owls who all screech and hoot intermittently. I'm squished, open book in lap, between one of the Patil twins and the window looking out into the busy corridor.

We're almost at Hogwarts so everyone is occupied with changing into school robes or visiting compartments to catch up with friends and show off the things they got over the summer. Through the smudged glass, I see Harry striding in our direction. The compartment door slides open and he barges in.

"Oy, where's my snitch?" he asks immediately. "I know one of you girls stole it. Dean told me."

He's met with a sea of innocent-looking faces.

"We didn't know you had a snitch, Harry," someone says. "It's not something you ever talk about." It's followed by a series of barely-suppressed giggles.

"Right," says Harry. He starts hauling random luggage off the racks, ignoring all the loud protesting. I move my knees out of the way. It's becoming impossible to read. One of the bags falls onto an owl cage. Its metal door springs open, and the bird flies out screeching madly. Someone throws themselves sideways, jostling me. My head hits the glass window.

"Argh!" I grunt, fed-up. "Stop this! It's with Ginny! Ginny's got your blasted snitch."

"Hermione!" Ginny cries. "Why'd you go and snitch on me for?"

There's more loud giggling. I ignore them; I've just seen Cho Chang walking down the corridor alone, and I've been wanting to catch her. I jump up and exit the compartment, squeeze past several second years, an annoyed trolley witch and her trolley stacked high with sweets and pastries, to tap Chang on the shoulder.

She looks over her shoulder and smiles politely. "Yes?"

I introduce myself. "Can I talk to you in private?"

Something gold and shiny buzzes overhead and we flatten ourselves against the wall as a few boys hurtle past us. It would appear Harry's recovered his snitch.

I sigh and turn back to her. "Er, later that is. When we get to school."

She raises an inquisitive brow. "I don't know if I'll have time later. Why don't we just talk now. The Prefects' carriage should still be empty." She pinks slightly. "I just came from there."

I remember that she's dating Cedric Diggory. "All right."

We make our way to the end compartment and slide the door shut behind us. I've never been in here before. It's cleaner; the leather seats are less worn and there are no empty sweet wrappers in the corners. Strings of pennants displaying each House's crest hang from the ceiling.

A pang of envy crosses my heart; I had been hoping to be made Prefect this year.

We seat ourselves facing each other. "I was hoping for some clarity," I begin uncertainly. "On… on our situation."

The only thing I am sure about, with regard to Omegas, is that it appears to be a somewhat delicate subject.

Her face lights up with immediate understanding. "Who is it?" she asks.

Who is what?

"Never mind, you don't have to tell me. Whoever it is, are they already on the list? Obviously, Cedric's not on it yet. But he'll present, I know it." I can hear the desperate hope in her voice.

"What is-" I rub my temples. "I'm sorry. Can you please explain from the beginning? I don't know anything about a list or presenting or who is or isn't on the list."

She stares. "Didn't your family tell you? Haven't you been matched yet?"

They had, in fact.

"You're an Omega, Hermione!"

That had been the gist of it.

"My family are muggles," I say. "They don't know anything. Can we start with what an Omega is?"

"All right," she says slowly, wearing the uncomfortable look I've come to associate with this topic. "Omegas are a type of witch."

I could scream.

"Go on," I prompt, forcing myself to remain calm. "What's wrong with them? Why does no one want to talk about them?"

She frowns. "You mean us. Well, it's like talking about sex. But weirder." She sits up straighter. "Right, you know how you can tell if someone is an Omega or an Alpha by their smell?"

I shake my head no, but things are beginning to make sense. All those tests at the hospital, and everyone assuming I already knew I was different. "Smells… We smell?" My nose scrunches in distaste. "That sounds… gross. Do I smell right now?"

She frowns again. "It's not gross. And you do smell. I mean you smell nice." She sighs frustratedly. "It's hard to explain, and it's strange that you can't tell. That's a pretty big part about being an Omega. Maybe you just don't know what it is you're smelling." She purses her lips quickly to one side. "What do I smell like to you?"

"Erm. I don't know," I say. "I can't really smell anything from here. Is it probable that everyone's made a mistake?"

"You smell like Omega to me." She pats the space beside her. "Sit here. Try smelling my hair."

I cross the short distance between us and bend my head close to her. This is weird. "Maybe shampoo?" I guess, squinting in concentration. "Roses?"

"Yeah, that's my shampoo." She laughs. "I think you're the first person to actually notice I use rose-scented shampoo. Everyone else just smells Omega. It's weird that you can't recognise it. You should be able to from here. Hmm. This isn't proper, but… try smelling my neck." She loosens her blue-and-bronze tie and pulls her hair into a ponytail.

"Okay." This is very weird. I lean in. "What exactly is it supposed to-"

The door slides open with a startling bang and I scoot backwards.

"Kinky," someone comments. Avery Gaunt stands in the doorway, arms folded. A green and gold badge glints on his chest. "Hm. I know people like you don't get to become Prefects so why are you in my carriage?"

My jaw drops. "You're the new Head Boy?" Of all the unfair things in the world. "And why wouldn't we get to become Prefects?" I add in indignation. "We're better fitted for the role than you!"

He begins laughing, almost howling with uncontained mirth. "Who would listen to you?" he manages in between gasps of laughter.

"Oh sod off, Gaunt," Cho Chang snaps.

It only makes him laugh harder. Finally, he straightens. "This is my carriage," he says. He points accusingly at me. "You. I've heard enough about you from my family this summer to last a lifetime." His finger moves to Cho Chang. "And you. Don't think I don't know what you and Diggory get up to in here. Both of you out. Now."

A witch and wizard gripping hands smile falsely at me from the front of their shiny pamphlet. 'MALFOY GLOBAL ASSET MANAGEMENT' reads the bold green heading.

"I've read this three times over and I still don't know what it is they do," sighs Lavender. Her face is hidden behind the pamphlet, but I imagine she looks annoyed.

"Our dad works there," Parvati says. "And even I don't know what he does."

"Manage assets, probably," says Ron sagely, mouth bulging with potatoes. Almost all the Gryffindors had their Careers Advice appointment with Professor McGonagall today. The remainder are due to see her on Monday. I haven't received the note with my appointment time yet, but really, I'm too busy revising to remind her.

Lavender folds the pamphlet with an even bigger sigh and drops it onto a messy pile. She picks up another one. "Black and Malfoy Apothecaries," she reads out loud. "A global potions company based in London. At Black and Malfoy Apothecaries we strive to set the standard for quality, safety, innovation… urgh." She puts down that pamphlet too. "This is really stressful. I wish somebody would just decide for me."

"Your OWL results will probably decide for you," I say, shutting 'Core Principals of Animal Physiology for the NEWT Transfiguration Student' with a snap.

Ron snatches it from my hands. "Why are you reading a NEWT textbook?" he demands. "You don't even need to take the NEWTs."

"Nobody needs to take the NEWTs, Ron," I say nastily, taking back the book and stuffing it into my bag. "You certainly won't be taking them at the rate you're going. They're not going to let you copy from me in the exams, you know."

I swing my leg over the bench and depart hastily before Ron can think of a comeback. Lavender's already reading from another brochure. "Oo this one's a fashion brand!" she squeals excitedly. "Maison Malfoy, a family-run multi-national… wow, do the Malfoys own everything?"

The steady scratching of quills on parchment fills the small circular room. I pause my own writing to appreciate it; I think it might be my favourite sound in the world. Around me my classmates whisper to each other under their breath. We're technically supposed to be solving a problem alone, but it's clearly confusing people.

Professor Vector is reading a magazine upside down. On the blackboard beside her, she's written out the problem in chalk. I read it for the fifth time.

'Jack is planning the optimum time to meet Rose for a date in London. He knows that Rose is twenty-five years old and an only child. If Jack has calculated that their date must take place at seven thirty-five PM on a Friday during the waning gibbous lunar phase when the moon is 72% illuminated and at latitude: 0 59' North, Longitude: 132 10' East, when was Jack born?'

I bite my cheek, attempting to add numbers in my mind, and bend my head to scribble the necessary equations, whispering also. "Kappa, epsilon, omicron, beta…"

My partner, Daphne Greengrass, yawns audibly and puts her blonde head in her arms. Normally I sit beside Padma Patil, but she's been excused for Careers Advice with Professor Flitwick. Arithmancy is a very small class and they've combined all the houses for it.

I sneak a glance at her calculations and immediately spot the glaring error. "The moon position's a red herring," I whisper, unable to keep myself from correcting her.

She lifts her head. "What?"

"The moon position's not relevant to his birthyear." No wonder people are having trouble with the problem. They're probably making the same mistake.

"Oh!" She perks up. "Thanks."

"Yeah no problem," I smile wryly, watching her cross out the wrong equations. "Didn't make sense that he would be thirty-nine, did it?"

"Sure," Daphne snorts, casting me an odd look. We resume writing, and after some time, she pauses to give me another look. "I'm really impressed you can still find it in yourself to care. But I suppose he's letting you continue after your OWLs?"

I lower my quill and give her a quizzical glance. "Who?"

She returns the expression. "Your fiancé? Who is he by the way? I haven't seen an official announcement."