I try to smile back, but it’s a shaky smile, and I decide to go and check on Elsa rather than just stand here being stared at.

I grab a handful of carrot puffs and pull back the flaps on her box. I peer inside. Everything is quiet and still. ‘Are you hiding?’ I say, pushing the balloons and cuddly toys to one side. ‘Elsa?’

The box is empty!

I see that some of the tape has peeled away, leaving a baby-sized gap. ‘Grandad,’ I hiss. ‘Elsa’s gone!’ Then I get down on my hands and knees and start searching under the table and around the various boxes.

Grandad double-checks the box. ‘Whoops!’

‘Whoops?’ I say. ‘Grandad, this site is basically a baby death trap: there are ponds everywhere, not to mention gigantic telescopes, moving floors, lasers, rocks …’

‘Don’t forget all the concrete steps,’ he says. ‘Well, she can’t be far away.’ He walks towards the exit. ‘She’s probably crawled under the tent. I’ll find her while you start the show.’

‘While I do what?’ I say.

‘Start the show!’ he bellows, as he strolls out of the tent.

Immediately, children are shushed, the audience falls quiet and everyone turns to look at me.

‘Yay, it’s starting!’ shouts a girl on the floor, bouncing up and down.

I stare down at her, my mouth slightly open. Did Grandad plan this? Knowing how nervous I feel, did he actually let Elsa escape so he’d have an excuse to throw me in at the deep end? My theory sounds mad … but Grandad is a bit mad!

I look up and face the audience. Sweat prickles under my arms and my mouth goes dry. There’s a cough, some more shushes and then the yay-girl says, ‘Who are you?’

‘Ummm …’

‘Your face is funny!’ she adds.

‘I … ummm …’ I swallow and grab Grandad’s notes, scanning the introduction. A lump has formed in my throat and I know that I can’t talk. I just can’t do it.

Suddenly, Yay-Girl shouts even louder, ‘WHO ARE YOU?’

‘I am the granddaughter of Copernicus,’ I say in a rush, ‘the man who just ran out of the tent. Well, he’s Copernicus and he’s an amazing man and –’

‘Why’s he so amazing?’ The boy who’s just interrupted me is sitting by my feet. He’s about six and he’s got a bored expression on his face. I feel a rush of irritation and for a moment I forget how scared I feel. ‘Copernicus is amazing because he’s one of the greatest astronomers who ever lived. Before he came along, everyone thought Earth – our teeny little planet – was the centre of the universe.’

The boy seems unimpressed. ‘I’m Isaac,’ he says, then he narrows his eyes suspiciously. ‘What’s your name?’

I glance at Grandad’s notes again, trying to find the name he thought up for me. ‘My name is Megernicus,’ I say.

‘We can’t hear you!’ shouts an adult voice from the back.