I look across at Granddad. He stares ahead. I’ve said I’m sorry twice, but now I want to say it a million times.

‘Granddad . . .’

‘It is okay.’ He takes the keys out of the ignition. ‘It was a long time ago. We do not have to talk about it any more.’

‘But . . .’

‘But nothing,’ says Granddad. ‘We have said all we need. I think we should go inside now. And besides, I have a plan. I will show you after tea.’

‘For the Stasi? Are they still around? Are they still in the towers, pointing their guns down at the Wall, at all the people scrambling over the barbed wire?’

‘No, thankfully not.’

‘So what’s the plan for?’

A smile creeps across Granddad’s face. ‘To beat this Rich, of course!’

I Can Keep a Secret . . .

(for thirteen hours, twenty-three minutes and twenty-five seconds)

‘Okay, everyone. Just draw the x and y axes first. Are we getting there? Who are we waiting on? Liam . . . Jake . . . Felix?’ A shadow creeps across my desk. I look up. I’m in maths with Mr Andrews and he’s standing right in front of me and Jake.

‘Come on, you two,’ he says. ‘Jake, at least Felix is trying but you’ve not even got your pen or ruler out.’

‘Sorry, sir,’ says Jake.

I put my hand over my mouth and try to stifle a yawn.

Mr Andrews tuts. ‘You need to stop playing Fizzer Motorsport all night, Felix.’

Jake laughs.

‘What’s so funny?’ asks Mr Andrews.

‘It’s Forza, sir,’ says Jake, ‘not Fizzer.’

‘I don’t care what it’s called; all I know is that something is stopping both of you drawing a simple graph . . . Now come on!’ He stares at me and Jake, then slowly moves away.

I pick up my pencil and ruler.

I am getting on with my work, but I’m so excited about the new move Granddad taught me after tea last night. We set the knives and forks, salt and pepper and all the other condiments out on the table again and he taught me the Maróczy Bind. It’s named after a Hungarian grandmaster and it’s used by lots of chess players to combat the Sicilian Defence. So now I’ve got two really good moves – one if I’m playing black, and the other when I’m playing white. I can’t wait to use it on Rich, but Granddad told me not to tell anyone about the move because one of the best tactics of chess is the element of surprise.

I draw the x axis.

‘Oi.’

I move my ruler vertically on the page.

‘Oi.’ Jake nudges me.

‘What?’ I say. ‘I’m trying to work and you just made my y axis go wonky.’

‘Oh well, never mind.’ Jake grins. ‘But where were you last night? I thought we’d agreed we were going up the tree.’