‘Right, you find some paper and I’ll give Elsa an orange. That should keep her busy for a while.’

Grandad and I spend the next half-hour making lists, drawing tables and working things through. When I was little and we played rockets, it was all about the mission. I’d put on one of Grandad’s shirts as a lab coat and we’d plan a trip to orbit Mars or land on Venus. We’d work out fuel supplies, distances and trajectories. I was so into the planning bit that sometimes we never got round to take-off. Plus, I was a bit scared of aliens.

Soon we’ve written a plan to cover the whole two weeks Mum will be away. Everything’s on there, even little slots for me to rehearse my speech for the competition. Just looking at it makes me feel more in control. I remind Grandad that we need some money; Mum didn’t leave any and she took her bank cards so I can’t take any money out of a cash machine.

‘I got my pension the week before last,’ Grandad says.

‘That’s good.’ Grandad’s pension comes in once a month so it should cover the time Mum’s away. ‘I guess you’ve got most of it left?’

‘Ah, well …’ He looks a bit sheepish. ‘I did buy something on Saturday: a white silky bantam.’

‘Really, Grandad? Another chicken?’

‘A beautiful chicken.’

I shrug. ‘I suppose we can always eat it.’

This makes Grandad laugh. ‘Not until we’ve eaten the one Pongo killed. I’ve got her all ready in the freezer.’

I remember that’s the ‘mangy’ one and make a mental note not to eat any chicken at Grandad’s for a while.

After we’ve taken the new bantam into account, we discover we’ve got one hundred and twenty-three pounds to keep us going until Mum gets back. The three pounds is leftover from the pocket money Grandad gave me last Saturday.

‘Loads of money!’ he says.

I’m not so sure. Sometimes Mum gets me to buy Elsa’s nappies and they cost a lot. I point at the first square on my mission plan: ‘Tues Evening’.‘I’m up to here,’ I say. ‘ “Elsa – bath and bed.” Easy.’ I push what happened last night to the back of my mind. ‘I’ll type this up later and laminate it.’

‘That’s my girl!’ says Grandad. ‘Now, do you want Pongo to stay here?’

We both look at Pongo: he’s standing in the corner of the kitchen, growling at a cupboard door. Pongo might be terrified of everything, even the wind and moths, but he looks scary. It’s not just the scars. His teeth are permanently bared and he has wild eyes. ‘I think I’ll keep him,’ I say, ‘for protection. Come on, Pongo.’ I clip his lead on to his collar. ‘Let’s get this mission started.’

SIXTEEN

Back in the flat, I follow every stage of the plan. I give Elsa her bath, do up all the little poppers on her Babygro, then hold her on my lap and stick a bottle in her mouth. Straight away she goes quiet, and just sucks her milk and gazes up at me, holding on tight to one of my fingers. I, meanwhile, gaze at my physics textbook and learn about kinetic energy.