"And to be clear: that's the last time I'll acknowledge that name," Olivia continues. I barely hear her. I'm zoning out...

I think I have one of those movie moments where the main character loses all focus and there's no sound but the droning whine of tinnitus. I know my heart is thundering away like nothing on Earth. I suspect my jaw has dropped, too, and made me look thoroughly gormless. Not a good way to ingratiate myself with the girls. Anyway, I must have zoned out for too long; all of a sudden, I become aware that the four of them are looking at me with an expression that very much seemed like concern.

"Harry?" Jessie's voice sounds oddly echoing. "Are you in there?"

I blink sharply and quickly. The girls' shoulders slump with relief. "He's fine," says Kiah.

And I am. Mainly. Except I still can't wrap my head around what Olivia has said. She definitely has something of my old primary school friend in her face—but softer, undeniably feminine. If it weren't for Jessie, Olivia would probably be the prettiest girl in the group. Which meant she must be lying. It must all be a joke at my expense. We boys were cursed to be hideous—we didn't get to be girls, and we certainly didn't get to be pretty, and no amount of wanting could change that.

After all, if it was possible for boys to become girls then there would be no boys left. Because every boy wanted to be a girl.

Right?

I point at Olivia. "You're Oliver?"

At once, Kiah reaches up and slaps my pointing finger down. "No," she hisses. "First off, it's rude to point. Second, she's Olivia, and she always has been, so don't you dare let me catch you using any other names for her."

"Sorry." My throat has gone dry. Kiah's scary. But I'm still confused—a million questions are running through my head, and I'm fairly sure only three quarters of them would be considered rude. "But you are the same person I knew as... a different name?"

Olivia nods. "I've always been a girl," she says, "but I didn't realise it until I started at secondary school. I knew I couldn't go on pretending to be a boy—I hated it so much, I'd go home crying—so I stopped pretending. Strictly speaking it's not an accurate description of what happened, but I suppose you could say I... became a girl. I changed."

There's a real risk I'll start staring again. To avoid that, I force my eyes shut and keep them closed for way too long, only ending up looking even weirder in the process. When I open them again, I can feel my shoulders shaking. I can barely even get any words out. "You can do that?"

Emma nudges Jessie. "Big egg vibes," she mutters. "Told you."

Olivia meets my probably-frantic gaze. "Yes," she says. "You can do that."

"Wow." My head is spinning. Why do I feel suddenly so excited? It's not like I would ever want to do what Olivia has done. I mean, sure, being a girl would be nice, but that's not who I am. After all, Olivia said it herself—she's always been a girl. Even back in primary school, when I and the rest of the world knew her as a boy. I, on the other hand, am nothing more than a boy. A hideous boy, not masculine enough to look like a man yet but too masculine to look like a child.

But a part of me wonders if perhaps I could do what Olivia did. Wear girls' clothes, go by a girl's name, do whatever it is Olivia's done to get such a cute, feminine body. Not at school, obviously. Everyone here knows I'm a boy. They'd laugh at me—or worse, they might take offense. Jessie and the girls would probably think I was mocking Olivia, and I could kiss goodbye to our burgeoning friendship. But I finish school in a year. I could go to a Sixth Form far away, where I wouldn't know anybody; and if I didn't know anybody, what would stop me from telling people I'd always been a girl? They wouldn't have to know, would they? They wouldn't have to know that I'm really a boy who just kind of wants to be a girl.

But no. I shake my head. Get a hold of yourself, Harry. You're a boy. Shit luck, but that's the way the dice fell, so suck it up or you'll never work out how to be a proper man.

"Are you okay, Harry?" Jessie looks at me with concern in her blue eyes. "You've been holding that sandwich for, like, five minutes."

Impossible, I think. I didn't even pick the sandwich up until Olivia was telling me she's my old friend from primary school, and that was, what, ten seconds ago? I stuff the sandwich, whole, into my mouth, regretting it immediately. It's disgusting to stuff your face so much, Mum always says as much, and in any case I'm not even hungry. The sandwich is wafer-thin chicken on white bread, dry as old boots, and I'd have to force it down even if I had an appetite. And my appetite has mysteriously taken a leave of absence.

I spend the rest of lunch in silence, picking my way slowly through the sandwiches and crisps Mum packed for me, listening to the girls' conversation. They seem at ease with me around, and—oddly—I find myself interested in what they're saying. Emma's describing her family's summer holiday to some resort village in Devon, and the others are listening. And when she finishes her story, they each chime in with phrases such as "it sounds so beautiful there" and "I bet you had a lovely time" and other nice touches that prove that they'd actually been listening. I'm honestly surprised. In my experience, conversation is superficial but also built around bravado. Even Tom only seems to pay attention to what I say to him half of the time, and I get the impression that that's usually in case he has a story of his own that could one-up mine. I actually get a bit sad, knowing that I have no friends who would actually care about where I'd been on my summer holiday.

I wonder whether the care is specific to Jessie's group of friends, or if it's just how girls talk. Either way, I want it.

The bell for the end of lunch rings just as Jessie's talking about her summer flame, her cheeks aglow as she giggles. I'm glad, to be honest. I don't want to know about the boy Jessie's interested in. That would just remind me that I'm not that boy. That I'm not man enough for a pretty girl like Jessie to be interested in. I pack my things away and say goodbye to the girls, thanking them for letting me sit with them, but as I'm about to leave, Jessie pulls my sleeve.

"You're not going to dash off like that, are you, Harry? We have English together, remember?"

"Oh." I blush a bit. "Right. I forgot. Still working on last year's timetable." Nice save, Harry.

"We had English on a Monday afternoon last year too," Jessie points out.

So much for my nice save. Now she probably thinks I was trying to ditch her. "Did we? Sorry, my mind's elsewhere." A lame excuse, but given that my offence—had I actually gone anywhere before she pulled me back—was minor, I figure that she'll shrug it off and we'll walk to English together, where we can resume our usual amicable distance.

I certainly don't expect Jessie to hug me. "It's okay," she says, squeezing me tightly in her arms. "I understand."

Do you? Good, because I don't.

"Thanks again for letting me sit with you today," I tell her, as we start off on our way to English. "I'll miss it tomorrow."

"What are you talking about?"

"I'll miss hanging with you and the girls," I explain. The library may have been my haunt for the last four years, but I just know it's going to feel a little lonely tomorrow.

Jessie looks confused. "Aren't you going to sit with us again?"

"You don't need to keep being nice to me," I assure her, with a chuckle. "I'll be fine. I don't want to intrude on you and your friends any more."

"Harry," Jessie says, "you're my friend. And Olivia's friend, and Emma's, and Kiah's. How can you intrude on the girls by sitting with us? You are one the girls. One of the gang. You can sit with us every day. Oh, and you know Sophie Polkinghorne's moved to St Anne's?" St Anne's is the private school on the other side of the city, where they all wear frock-coats with tails and learn Latin and probably sacrifice one of their number to the god Mammon every full moon or something. Sophie Polkinghorne was in our English class. I never liked her. Though in fairness, I never liked most people in the year, so that's no indictment on her in particular.

"I didn't know that," I tell her. "What about it?"

Jessie's lip curls into a grin. "Sophie used to sit next to me in English, so now I need a new desk-buddy. What do you say?"

What do I say? Honestly, that I'm beginning to feel like the victim of an elaborate trick. This has been a weird day already, but now Jessie Porter wants me to sit next to her in English. Jessie Porter considers me a friend. This is a bloody upside-down world. But I'm here for it. "I'd love to be your desk-buddy," I tell her. Jessie squeals in delight.

*

English, to my chagrin, is held on the top floor of the school's main building, in a corner room with windows along two sides. On hot days it's hell: a veritable furnace, where the sun hits you wherever you sit and the heat takes an age to escape. Today is a hot day. Just stepping into the classroom is like putting my face in an oven.

I have no idea how Miss Jorgensen does it. My favourite teacher, partly because she's pretty in a way that I'm always oddly envious of, she always has her makeup done immaculately. I've heard Beth complain often enough to know that makeup in sweaty weather is a pain in the arse at best. And yet even in today's stifling heat, Miss Jorgensen is done up as beautiful as ever.

Jessie tugs my hand as we enter. "Next to me," she says. "Before someone else tries to." She leads me to her usual desk at the back of the classroom, next to a wall which bears a sun-faded poster of literary devices represented by cartoon figures. As we walk to our seats, so the class watches. My face burns. I can hear the whispers in their stares. Who does he think he is, sitting next to Jessie? The loser's getting uppity.

Even Miss Jorgensen seems surprised to see me next to Jessie. To her credit she hides the surprise well, but there's no mistaking the momentary blink. "Good afternoon, Jessie. And, uh... Harry? Is Sophie not joining us today?"

"She's moved to St Anne's, Miss," says Jessie. "So Harry's sitting next to me this year. Is that alright?"

"Quite alright," says Miss Jorgensen. "I'll amend my seating plan."

It's a fairly mundane lesson. Miss Jorgensen calls out the register, then runs us through an overview of the topics ahead. Halfway through I'm bored. I've decided I don't care what we have to study; I'm happy to just bask in the joy of actually having someone I can sit by. And a cute girl, no less.

Clearly this is my year. Preordained by fate. How else would the first day have led to such a marked change in my social outlook? I might even get a girlfriend before Tom does, if I play my cards right.

I'm barely cognizant of what's going on as Miss Jorgensen moves around the room handing out books. We're reading To Kill A Mockingbird this year, apparently. I don't know what it's about. Right now, I don't have the headspace to think about it. I'm very much distracted by other things. Important things.

What would I be called if I was a girl? Harry's short for Henry—why they say 'short for' when the two names are the same length I'll never know—so maybe I'd have been a Henrietta. I'm glad I'm not. That's the sort of name a St Anne's girl would have. What other girls' names begin with 'H'? Holly. Hillary. Hildegard. Or maybe I'd have had a name that begins with a different letter; Harry's a fairly bog-standard name, so perhaps I'd have been something equally common. Ellie or Maisie, Sarah or Alice. Hannah, perhaps.

Yes, I could imagine that. Hannah seems to sit nicely in my mind, and when I try it on my tongue it feels right. In a weird way, it seems to feel more like my name than Harry does. If I ever decided to pretend I was a girl, Hannah would be the name I'd pick.

Hannah. Han-nah.

Miss Jorgensen looks out of the window at the bright sun outside and sighs. "There's not much point starting any of the assignments now," she says. "Why don't you all just make a start on your reading?"

Which, as I predicted, is the cue for the class to start talking in hush-tones. Whenever Miss Jorgensen's back is turned, Eddie and Joel—heavy-set lads, the only two on the rugby team who are smart enough to make top-set English—turn to glare at me. They've done that for years. I don't know why they hate me, but they do. For the first time ever, though, I'm not sat on my own. Jessie flips them both off, and puts her hand on mine. "Ignore them," she tells me. "They're dickheads."

"I know." I sit in silence for a minute, then, my copy of To Kill A Mockingbird open but the words not going into my brain. "Jessie, when we were walking to class you, uh... said I was one of the girls. Did you mean that?"

"Oh, shit, sorry. I didn't mean it like that. I just meant... you're one of us, part of the group. It doesn't matter whether you're a boy or a girl. But I shouldn't have phrased it like that. Did I upset you?"

"No," I say, shaking my head. "I actually kind of liked it."

"Well, there you go then," says Jessie. "You're one of the girls."

So there would be a puzzle for me to ponder tonight in bed. Why do I feel so damn giddy when Jessie calls me one of the girls?