The insistent beeping of my alarm clock pulls me out of a super-weird dream. Something about talking dolphins and the end of the world, I think.

It’s funny how that moment in a dream just before you wake up can seem like the most real moment there’s ever been. You completely believe that it’s true – that it’s really happening to you – even if you are talking to a dolphin at the time. But then when you open your eyes, the dream starts to fade straight away and all that you’re left with is a strange jumble of thoughts that don’t seem to make any sense at all.

Fumbling for the button on top of my alarm clock, I shake the last of the dream fragments from my mind, my eyes blinking in time with the numbers displayed on the digital screen.

9.00 A.M.

For a second I panic, wondering why nobody has tried to wake me up yet, but then I clock the date.

SATURDAY 9 JUNE

It’s my birthday.

Jumping down from my cabin bed, I pull open the curtains and sunlight floods into my room. Through the window I can see the gazebo that Mum and Dad have bought for my birthday party laid out across the lawn beneath protective plastic sheets, just waiting now for Dad to put it up. Over the back fence I can see the railway tracks, and beyond this the backs of the shops that lead up Cheswick Hill, the whole scene bathed in perfect summer sunshine.

I can’t stop myself from grinning. Today is going to be the best day ever. I’m ten years old.

The ancient Greek philosopher Pythagoras thought that the number ten was the most important number in the world. He basically invented maths using it and reckoned that the whole universe was built out of numbers. Pythagoras said that the number ten contained the key to understanding everything. So, if this is true, I reckon being ten years old is going to be pretty cool.

Maybe now that I’m ten, Mum and Dad will let me go to the shops on my own or even stay up late, just like Lily.

Lily’s my older sister. She’s fifteen years old and she hates me.

Mum and Dad say that Lily doesn’t hate me. They say she’s just a bit stressed at the moment because she’s revising for her GCSEs, but I don’t think this is a very good excuse. I passed GCSE maths when I was six years old, and physics, chemistry and biology when I was seven. Then I did my A levels and now I’m studying for a degree in Mathematics and Physics at the Open University.

The thing is I’m “academically gifted”. Apparently this puts me in the top two per cent of the population. That doesn’t mean I’m smarter than everybody else. I’m absolutely rubbish at French. I just love learning about how the universe works. Lily thinks this makes me a freak.

Like I said, she hates me.

Pulling on my dressing gown over my pyjamas, I head down the stairs. The house is so quiet. Usually Dad’s already in the kitchen by now, noisily cooking up one of his Saturday-morning fry-ups, while Mum sits at the kitchen table reading the newspaper.

I turn right at the bottom of the stairs, heading down the hallway and into the kitchen. Beneath my bare feet, the black-and-white tiles covering the floor feel freezing cold. I shiver. The kitchen table is deserted, the cooker standing silent as the empty work surfaces gleam. There’s nobody here.

I peer through the patio doors that lead out into the back garden, wondering for a second if Mum and Dad have sneaked out there to make a start on putting up the gazebo for my party later today, but there’s nobody there either.

Maybe they’re hiding somewhere and are going to jump out any minute singing “Happy Birthday” to me.

“Mum! Dad!” I call out. “Where are you?”

I stand still for a moment, ready to look all surprised when they suddenly appear. But nobody jumps out. The grin I’ve been wearing since I opened my bedroom curtains is slowly starting to fade. If Mum and Dad think this is funny, I’ve got news for them.

The living room is just as empty as the kitchen, the TV switched off and not a cushion out of place on the sofa. I’m not surprised that Lily’s not up yet, as she doesn’t usually surface until after ten at the weekend. It’s all to do with the fact she’s a teenager and the hormones in her brain that make her sleep late. Maybe that will start happening to me now that I’m ten. Now that I’m ten, everything might change.

I’ve done a circuit of the downstairs now: hall, kitchen, living room and back to the hall. If Mum and Dad really are hiding somewhere ready to give me a birthday surprise, then they’re running out of rooms. Our house really isn’t that big.

Standing at the bottom of the stairs, I call out again.

“Mum! Dad! This isn’t funny. Where are you?”

Still no answer – just a creepy silence that seems to fill the house. I shiver even though sunlight is streaming through the arch of tinted glass at the top of the front door behind me. Where is everyone? They wouldn’t have gone out without me. The excitement I felt when I sprang out of bed has now turned into a nagging sense of worry. I race up the stairs, two steps at a time, wanting this stupid game of hide and seek to be over already.

Heading round the landing, I push open the door to Mum and Dad’s bedroom.

The room is still in darkness, the curtains drawn against the morning sun, but in the light spilling in from the landing I can see that nobody’s here. The bedspread is pulled neatly across Mum and Dad’s king-size bed. It doesn’t look like it’s even been slept in.

The twisting worry that’s been coiling inside my stomach is now tightening into a tense knot of fear.

Doubling back along the landing, I glance back inside my bedroom and then peer round the bathroom door too, just to double-check. But both rooms are empty, the only living thing I can see is a spider scurrying towards the bath taps when I pull the shower curtain back.

I shiver again, the sunlight streaming through the bathroom window seeming to lack any kind of warmth. Something’s not right.

Back on the landing, I glance towards the second flight of stairs that lead up to Lily’s room in the attic. A NO ENTRY sign is stuck to the wall at the bottom of the stairs and beneath this Lily has written “NO SISTERS ALLOWED”.

She means me.

I wouldn’t normally dare to go anywhere near Lily’s room on a Saturday morning. Her rage can be positively volcanic if her weekend lie-in is disturbed. But this isn’t a normal Saturday. It’s my birthday and I want to know where everyone is.

“Lily!” I shout up the stairs, my words echoing off the empty walls. “Are you up yet?”

There’s no answer.

“Lily?”

More silence.

I glance at the NO ENTRY sign and then shake my head. This is an emergency.

Taking a step forward, I start to climb the stairs. Inside my head, I quickly flick through the excuses I’ll use when Lily freaks out at me for waking her up. I don’t know what I’ll do if she’s not in her room.

Our house is usually filled with noise, but this silence is really starting to get to me.

Then the doorbell rings.

I jump in surprise, but as soon as I realise what this means, a sudden wave of relief washes over me. This must be Mum and Dad. They must’ve got up early to get things ready for my party and then realised that they needed something from the shops. Leaving me and Lily in bed they popped out and are now back with bagfuls of party stuff and need me to let them in.

I race back down the stairs, skipping round the landing and then barrelling down the second flight of stairs. It’s time to get my birthday started at last.

Reaching the hallway, the sound of the front doorbell seems to stretch out as if someone has left their finger on it for too long. Then it stops abruptly and the air hums with absolute silence again.

It must be broken.

Feeling kind of puzzled, I fix a smile to my face, eager to find out exactly what Mum and Dad have got me from the shops.

But as I open the front door this smile is suddenly eclipsed as my lips stretch wide in a silent scream. The sound of my cheery hello curdles in my throat as I look out in horror at the scene outside.

There’s nobody there.

But worse than that, there’s nothing there.

No Mum. No Dad. No car parked on the drive. No driveway. No street. No houses.

Nothing at all.

Just an empty black space that goes on forever.

I stare into the darkness, trying to make sense of the impossibility of what I can see.

It doesn’t work.

I slam the door shut before my brain explodes.

Gasping for breath, I stand there swaying, my hand still gripping the door handle as I try to work out what’s going on.

Looking down I see a rainbow stripe of colours dappling the polished floorboards, the sunlight streaming in through the tinted glass creating this shifting pattern. But when I opened the front door there wasn’t any Sun in the sky. There wasn’t any Sun. There wasn’t any sky. There wasn’t anything.

Feeling really frightened now, I back away from the door. If there’s nothing out there, who was ringing the doorbell?

Stumbling down the hall, I retreat to the kitchen, slamming the door behind me to try and block out what I’ve just seen. Still shaking, I slump against the kitchen table, my fingers trembling as I cling to its edge to stop myself from falling down.

What’s happening?