bicycle helmet that I was wearing and turns it upside down. The inside surface is dotted with tiny metal bumps.
‘Everything we see and hear and touch is processed in the brain. Without our brain, there’s nothing. Are you with me?’
Ramzy and I glance at each other, unsure where this is going, but Dr Pretorius isn’t even looking.
‘But your brain can be tricked. Optical illusions, magic tricks, déjà vu – they’re all tricks of the mind. We’ve been doing it since we lived in caves. And now this!’
She holds the helmet aloft like a trophy, glaring at us.
‘This, my friends, is the greatest illusion of them all. Or will be. The projector here –’ she runs her finger round the curved metal band that sat above my forehead – ‘deceives your eyes into seeing whatever scene is programmed. No more heavy goggles! But it is these that make the big difference. These nodes here, and here, and here …’ She’s pointing out the little metal bumps on the inside of the helmet that connected with my skull. ‘They send signals to the parietal lobe, and …’
‘Wait,’ says Ramzy. ‘To the what?’ I’m glad Ramzy’s here. For once, his habit of questioning everything is not an annoyance.
Dr Pretorius looks unhappy to be interrupted, but then she says, ‘It’s OK. It’s taken me a lifetime of study to understand this. The parietal lobe is the part of your brain that deals with touch and sound, and the other senses. With careful programming, the computer here can deliver signals to these nodes that will in turn send little electrical impulses to your parietal lobe and trick your brain into feeling, say, heat from a virtual sun. That’s actually an easy one. Sand is much trickier: to actually feel very fine grains running through your hands? That’s quite an illusion. I’m rather proud of it. Another cookie?’
I give her a blank look. I’m still trying to process this, and biscuits are not going to help. Ramzy, on the other hand, clearly thinks that they will help, and takes two more.
‘So, when I kicked the … that scorpion thing, it was what – a trick of the mind?’
‘Exactly! Just like the sand. The program tricked your brain into believing the scorpion was solid, and your foot felt it, just like your hands felt the sand – even though neither was there.’
‘And when I threw the deckchair –’ says Ramzy, spitting crumbs – ‘obviously, the chair just went straight through it.’
Dr Pretorius winks. ‘Smart kid. Though that’s something I’m working on.’ Then suddenly she claps her hands and gets to her feet. ‘Enough for today! There’s a lot more I have to do before it’s complete.’
‘You mean it’s not finished?’ queries Ramzy, taking the last biscuit as he hops down from the desk.
She says no more. Ramzy and I are silent as we follow Dr Pretorius out of the studio with Mr Mash and down the metal stairs to the empty loading bay. Instead of going to the door we came in, though, she doubles back and unlocks another door with a large, old-fashioned metal key.
‘Short cut,’ she says.
The door opens into the interior of the Spanish City arcade. There’s a noisy room full of slot machines and kiddie rides, the Gelato Parlour (which is just ice cream if you ask me), the expensive fish-and-chip shop and the Polly Donkin Tea Rooms. It feels like we’ve come through a secret entrance, although it was just a locked door.
The main arcade is a few metres in front of us, and we push through the crowd, but then I have to stop. Sass Hennessey’s mum has just served a plate of chips to a table outside the cafe when she catches my eye.
‘Hi, Georgie!’ she says as if Sass and I are best friends. Ramzy grins at her, even though he doesn’t know her, I don’t think. ‘Nice to see you, pet. And, er …’ She looks at Dr Pretorius curiously, probably wondering who she is.
I mumble, ‘Hi.’
‘How’s St Woof’s, Georgie? Saskia’s told me all about it,’ says Sass’s mum, gathering glasses from a table. I’m already hurrying towards the entrance and don’t answer. There is something in the way she looked at Dr Pretorius that has unnerved me.
I could be wrong. Maybe she does know who she is. Maybe Dr Pretorius is a regular in here. What do I know?
Dr Pretorius leads us out on to the busy street. ‘Come back same time tomorrow. And don’t forget: this is our secret! You ain’t seen nothin’ yet.’ She turns and goes back the way we came, and Ramzy and I watch her white hair bobbing above the crowds.
‘Well. That was pretty adventurous, wouldn’t you say, Georgie? Hey – Earth to Georgie!’
I’m miles away, staring up at the blacked-out upper windows of the Spanish City dome.
‘What can she mean, Ramzy? You ain’t seen nothin’ yet …’
‘Dunno. We’ll probably get to test out some weapons or something: the Battle of the Giant Scorpions! Or …’
‘No. I don’t think so. This isn’t about games. This is about something else.’
Ramzy gives me a quizzical squint. ‘You don’t trust her?’ he says.
I think about this.
Don’t trust anyone who doesn’t like dogs.
Dr Pretorius was OK with Mr Mash. She definitely didn’t dislike him. She even tolerated his smelliness. (He dropped what Dad calls ‘a proper beefy eggo’ in the control room and she pretended not to notice. That was nice of her.)
On the other hand, we only met her this morning, and she’s already sworn us both to secrecy.
‘I don’t know,’ I say to Ramzy, eventually. ‘But there’s something going on.’
‘Well,’ he says, ‘let’s find out. Same time tomorrow. It’ll be an adventure.’
I smile at him. ‘OK.’
So that’s that. We’re trusting her, for now.
And mad scientists have to be mad for a reason. Right?
For the next few weeks, our afternoons after school with Dr Pretorius settle into something of a routine. She never calls us on our phones, and we have no way of contacting her other than thumping on the door with the wolf’s-head knocker at a prearranged time and day. It is all very ‘old-school’ as Ramzy says, clearly thrilled.
Once inside, we sometimes test a new MSVR environment. Other times, though, we just hang out in the control room, watching, mesmerised, as she programs her computer to create new worlds for us to explore.
Once I had a headache afterwards, but it didn’t last long. Ramzy too. Dr Pretorius didn’t seem overly concerned, and gave us each a paracetamol.
(It turns out that it’s definitely a copter-drone under the blue tarpaulin, by the way. One day it was uncovered and lying flat: a bucket seat in the middle of ten spokes, each with rotor blades attached. It’s obviously home-made: there are exposed wires, and lumpy welding, and one bit beneath the seat is made from the bent lid of a McVitie’s biscuit tin. Dr Pretorius saw me staring and said, ‘Yup. That’s my next project. Solar-powered too: unlimited range.’)
And all the time we’re there, in the Dome, Dr Pretorius keeps telling us that we ‘ain’t seen nothin’ yet’. That there’s going to be a Big Experiment, although she won’t say what it is. She does check that we are keeping it all secret, though, by saying things like:
‘No