I hold the sealed envelope in one hand and tap it against the table thoughtfully.

HANNAH

I am holding Jay responsible for the fact that we are running so very late, disturbing Mum and Robert so that both of them slept through the alarm. Mum is so flustered about getting me to my exam that she actually runs through an amber-to-red light and spends the next three minutes of the journey worrying whether she’ll get caught. I twist in the too-small space in the passenger seat, trying to stop my back from feeling so bruised and tell her not to worry, loads of people do it every day and never get caught — she’d be very unlucky to get nabbed the one time she did. When she mutters something about having the worst luck of any woman she’s ever met I fall silent.

I’m bad luck, am I?

My belt is unclicked and I’m ready to leap out the second the car jolts to a halt, the door swinging shut behind me, cutting off my mum as she calls out my name.

AARON

I’m hanging back by the entrance hall, waiting, when I hear the creak of the doors to the foyer and I see Hannah walking in.

“Aaron, get in here, please.” Mr Dhupam steps out and ushers me into the exam.

HANNAH

I am wickedly uncomfortable. I had a bit of backache when I woke up and, now I’m sitting at my desk, it’s worse than when I was in the car. Maybe it’s all the stress? The lack of sleep? I thought I saw Aaron waiting for me, but I’m finding it hard to focus on anything else other than the pain in my back. I hear the call to turn over our papers and I scan through the list of questions. This paper looks rock hard. Shit. I’ve got to try.

My back is killing me.

I can’t even make sense of these questions. Perhaps I shouldn’t have chucked my Biology notes at Jay when I needed them this morning for some last-minute cramming?

Why is my back so bad? Maybe I’ve been sleeping funny or something.

Focus, Hannah. You need a not-entirely-shit grade today.

I’m trying to get comfy and concentrate on making sense of at least one of the questions, but it’s hard because THEY MAKE NO SENSE.

I shift in my seat, but that’s not helping. I glance over at Aaron and see that he’s finished one page and now he’s looking at the next. I watch as he curls the top left corner of the page he’s reading between his finger and thumb.

Shit. That hurt. I rub my back. I’m wondering whether I’ve pulled a muscle sitting funny when I feel something damp between my legs.

Oh God. I don’t need to look down to know what that is. Waves of back ache plus wetting myself can only mean one thing: I’m in labour.

Mr Dhupam comes over with some more paper when he sees my hand in the air.

“My waters have broken,” I hiss at him, trying not to panic. I’m due any day now but everyone told me first babies come, like, two weeks late and I feel wildly unprepared. This might be totally normal, this might be what’s meant to happen, there might be nothing to worry about, but I’d feel a lot better in a hospital surrounded by midwives instead of in an exam hall packed with stressed teenagers.

“You OK?” It’s him. Aaron. He’s crouching beside me, his hand on my back as if he never even noticed the silence between us. It makes me want to cry with relief. Only, hello? In labour. Crying with relief is not a priority right now.

“I think this is it,” I say and we look at each other. We have trained for this.

“My dad’ll drive us,” he says with less than a heartbeat’s hesitation. “Come on.”

Aaron helps me up and guides me down the aisle. I hadn’t realized exactly how much my back was hurting until I stand up, and I’m aware of the wet footprints I’m making on the floor. Anj is frantically trying to attract my attention, but she catches me during a twinge and I just sort of flap at her. I hope she doesn’t think I’m rude. I hear whispers as I go past the others, Mr Dhupam desperately calling for silence.

Aaron shouts at a kid hanging about in reception to go and get his dad from the staffroom and I call Mum on Aaron’s phone. It doesn’t matter how mad I am with her, she’s still my mum and I still want her to be there. It goes through to voicemail. I don’t think it’s right to leave a message, so I try Robert instead.

“Hello?”

“Hi, Robert. It’s Hannah.”

“Whose number is this? I thought you had an exam. Is everything OK?” I can tell he’s on the handsfree in his car.

“Um. I think I’m in labour.”

“What?”

“My waters broke during Biology.” There’s a lot of swearing on the other end of the phone and I almost have to shout for him to get my hospital bag from the baby’s room. “Can you ring Mum?”

“I’ll go and pick her up. Or…” A pause then, “I don’t think Jay’s set off yet. He could…”

You can tell he’s thinking that Jay could fetch Mum on his way to the hospital.

“I don’t want Jay,” I say, glancing up at Aaron, who’s chewing the skin on the side of his thumb as he watches me. “Aaron’s with me.”

Another pause. “OK then. I’ll see you in a bit.”

“Don’t worry, Robert. I’m fine. The contractions don’t hurt that much.”

By the time we get to the hospital I’m thinking that contractions hurt a shitload.

AARON

Hannah is behaving as if she’s calm, but you can see she’s terrified, even now they’ve hooked her up to a monitor, which she’s watching like a particularly thrilling episode of EastEnders.

“Han?”

“Uh-huh?” She looks at me, back at the baby’s heartbeat, then at me.

“So when your mum gets here I’ll call Dad and see if he can pick me up after lunch.” She looks bewildered. “Before lessons start this afternoon.”

She closes her eyes and frowns. That’s a contraction. She’s been going silent and frowning about every five minutes since we got here. I wait.

“Can you stay here?”

“What in the visitors’ bit? I’m sure—” She’s shaking her head.

“With me. Please?”

I don’t know what to say. We never talked about me being here for the actual birth — it was always going to be her mum, Paula, who I’ve just discovered confiscated her daughter’s phone so she couldn’t even speak to me… “Your mum will be coming soon—”

“She’ll just have to get over it. I need you.”

I look at Hannah for a while. She looks determined — and vulnerable. I think about Jay’s Post-it note: Take care of her. Standing up, I lean over the bed to kiss her cheek and press my forehead to hers. Jay was right — he didn’t need to ask.

“I want to be here.” So much that I can’t find the right words. “If you want me to stay, then I will.”

She screws her face up again and nods.

“Stay north side though, yeah?” she says through clenched teeth.

“I went to the antenatal class, didn’t I? I don’t need the live rerun.” And, in spite of her discomfort, she laughs.

HANNAH

I am in a world of pain. Contractions are unbearable. There is nothing I can do to get comfortable. If one more person tells me that it’s not going to be too long now then I will tear their face off. Seven centimetres dilated is nothing. I’d like to rip them a seven-centimetre dilation and see whether they agree. No, I don’t want to fucking eat — that would require I actually had a second in which I could unclench my teeth. If Aaron tries to stroke my hair again, I swear I will break every single one of his fingers. I want to be left alone but not too alone. I got angry when Aaron went to get something to eat and even angrier when he brought back snacks for Mum and Robert because I wanted to be left in peace for a change. I have walked, I have squatted, I have bounced on a stupid bouncy ball, I have kneeled on all fours and laid on my side and NOTHING MAKES IT FEEL ANY BETTER.

THURSDAY 10TH JUNE

3.07 A.M.

HANNAH

There’s a lot of noise around me. Mum’s weeping and Robert’s hugging her and squeezing my shoulder. The midwife is telling me well done and that I’m a good girl and I feel like my eyes have tripled in size from all the pushing.

There’s a scratchy kind of a wail from somewhere in the room and I reckon that’s my baby. I don’t know if it’s a boy or a girl — they showed me its bits, but I’m tired and confused and I didn’t really know what I was looking at. Someone’s giving me an injection to prompt the afterbirth, which is a thing I really do not want to see. It’s like there’s an army of people in pink scrubs — is that to disguise all the blood? There’s more blood than I thought there’d be…

My eyes sting from sweat and my arms and legs feel like the muscle’s been sucked out and replaced with jelly.

“Aaron?”

“Here.” And he is. He’s standing beside my head, his hand resting lightly on my sweaty hair. “You OK?”

“Where’s the baby?”

“They’re just grading it or something.” He points to a huddle by an incubator. “Weighing, checking, marking out of ten.”

“Is it a boy or a girl?” I whisper, not wanting everyone to know that I don’t know.

“Erm, I didn’t see and they’re not really saying much.”

“It’s OK, isn’t it?”

“Yes. Definitely OK. No one is looking worried except you. CTFO, all right?”

I grin. Aaron never uses letters when words are an option. He’s looking at me weirdly. “What?”

“Nothing.”

“Mummy, are you ready for your baby?” The midwife, who may or may not be called Nicky, is holding something in a white towel. She’s holding my baby and then she’s laying it on my chest.

OH MY GOD, THIS IS MY BABY! I HAVE A BABY. THIS IS INSANE.

I think my face is going to break in half from smiling. I don’t care that this little person is purple and funny-looking — he? she? is AMAZING.

“What are you going to call her?”

“Her” — Nicky just said “her”. I have a little girl. A LITTLE GIRL!!! I want to scream with happiness. I have a daughter. I AM A MUM.

“Hannah?”

I look up at my mum and Robert, who are peering over my shoulder at the baby resting on my chest. I can feel Aaron’s hand stroking my hair the way it has been stroking my hair for over twelve hours. I look at the baby, just for a top-up, then at Aaron and grin.

“What’s she going to be called?” he asks.

I look down at my baby and see her tiny fingers uncurling and I watch as Aaron puts his little finger in her grasp. I stroke her cheek and she turns towards the feel of it. Look at the amazing little person that I made! I think about all the trouble she caused, the heartache, the lies, the betrayal. But she didn’t cause any of that, did she? Not this little person. Her life starts with a clean slate — the way Aaron’s did.

I glance up at him and smile, then I look back at my baby. I will name her after the most important person in her life. The most important person in mine.

“Her name’s Tyler. Baby Ty.”

AARON

I stare at Hannah.

I once told Neville that I needed to do something that mattered — I guess I did.

“Here.” She lifts her baby towards me. “Cuddle your fake daughter.”

ACKNOWLEDGEMENTS

I never used to see the point in acknowledgments. (I know, what a douche.) Fortunately I’m a better person these days and I’ve learned that you need to tell people when they’ve been awesome, just in case they don’t realize.

Thank you to Denise Johnstone-Burt and Annalie Grainger — not only for being my favourite editors, but for being two of my favourite people. You have made Trouble the book I wanted to write. And to everyone at Walker Books, including but not limited to Daisy Jellicoe for being thorough and lovely, and Jack Noel for being visionary and creating “The Sperm One”. At S&S US, thank you to both Alexandra Cooper, who spotted this, and Christian Trimmer, who ran with it so unbelievably awesomely. A writer can never have enough editors.

The biggest of all possible gratitude to my awesome agent, Jane Finigan — for finding a title, for finding the right deal and for loving this book more than I do. And for being brilliant on email. And in person. And generally. Actually, the whole Lutyens and Rubinstein crew are pretty brilliant.