Sam and I have agreed to concentrate on the mission first and think about what happens after it … later. As Sam said, ‘We might as well enjoy ourselves while we can.’ So when we have a Bangers and Mash meeting in Mission Control on Saturday morning, we’re both excited. We’ve developed codes so that we can talk about spy stuff when we’re out in public without anyone knowing. ‘Bangers and mash’ means a meeting about a spy mission. I love bangers and mash. Both kinds.

‘So,’ says Mum, gesturing to us to sit down. ‘Your next mission is connected to mine. I need you to collect some packages containing extremely valuable items for me.’

‘That doesn’t sound very complicated.’ I can’t help feeling disappointed. Sam and I are used to planting spy equipment and following suspects, not just picking up a few packages!

‘Just because it’s straightforward doesn’t mean there isn’t an element of danger,’ Mum says, shooting me one of her that’s-quite-enough-from-you looks.

‘Good.’ I grin over at Sam – what good is a spy mission if there isn’t a bit of danger? Sam grins back.

‘Your mum’s mission is a sting operation,’ Dad says. ‘Which is when you set out to catch an enemy in the act of doing something bad.’

‘Like stealing?’ Sam says.

‘That’s right,’ Mum replies. ‘But in this case we’re trying to catch an agent of ours who’s sending our newest and most top-secret spy gadgets out to enemy spies.’

‘Why would he do that if he’s on our side?’ I ask.

‘He’s a double agent,’ Dad says. ‘That means he’s pretending to work for us while he’s actually working for our enemies, giving them secret information about what we do and how we do it.’

‘He’s using Dan McGuire to do it too,’ Mum adds.

I blink at her. ‘Dan McGuire is a character in a book – how could he have anything to do with it?!’

‘He’s taking our spy gadgets and packaging them up in boxes of Dan McGuire merchandise so no one knows they’re real,’ Dad says. ‘It makes it easier to smuggle the spy gadgets over to the enemy if they look like a delivery of toys.’

I’m speechless. How could anyone use Dan McGuire’s name like that? That’s like Father Christmas stealing sweets from kids! Or the Easter Bunny chucking eggs at chickens!

‘So you’re going to stop him,’ I say to Mum. It comes out more like a command than a question but she must understand how I feel because she nods.

‘Don’t worry. I will.’

‘Well, we’re definitely going to do everything we can to help the mission,’ I say. ‘Right, Sam?’

‘Right.’ Sam is a big fan of the Dan McGuire books too, though she may not like them quite as much as I do (I bet she didn’t have the last book pre-ordered one hundred and ninety-two days before publication). But she still likes him enough to look (almost) as shocked as I feel.

‘The plan is to give the double agent some gadgets and make him believe that they’re our newest and most top secret,’ Mum says. ‘The gadgets will be planted with specially designed micro-technology that will track where the gadgets are taken, record conversations, take photographs and send alerts back to HQ when they come into known enemy territory.’

‘Will they be real gadgets or fake ones?’ Sam asks.

‘They’ll perform a few spy functions to fool the enemy spies into thinking they’re the real thing but it won’t be anything that involves our best technology,’ Mum says.

‘Basically the mission is to catch the double agent in the act and ensure the enemy spies don’t uncover any more of our secrets,’ Dad says.

‘To make sure he takes the bait, I’ll have to meet with him, giving him the primed gadgets – collected by you – so we can track them and prove that he’s been sending them over to the enemy,’ Mum goes on. ‘Then, after that, I’ll arrange a meeting so he can be caught by a special team from HQ.’ Mum looks at me. ‘You see, picking up these gadgets is extremely important work. HQ think the mission is less likely to be uncovered if you make the collections for me. You’re in a perfect position to collect the packages in locations that won’t be suspected, like your school, and you’re also less likely to be noticed because of your age. But remember, Josie, you’re to make sure that your identity remains a secret – being uncovered now would put the enemy spies back on our trail as well as ruining the mission.’

‘Understood,’ I say. As if I’m going to do anything to put my return to boydom in danger! I feel a lot more cheerful about this mission now I know there’s a bit more to it. We’re not playing postman, we’re catching a double agent and protecting the good name of Dan McGuire!

‘It sounds a bit dangerous for you though,’ Sam says to Mum.

‘You’re right, Sam, it is dangerous,’ Dad says. ‘And that brings up something else.’ Dad coughs. And I know that bad news is coming the way a footballer knows he’s about to get a red card.

What?’ I narrow my eyes at him.

‘Your mum will be doing this mission under a different cover from her current one. When she meets the double agent, she’ll be pretending to be a spy-gear specialist from HQ. That way he’ll believe he’s discovering HQ’s top secrets and won’t suspect that she’s a loyal spy trying to uncover him as a double,’ Dad says. ‘But it means she’s going to need a body double. Someone to be seen going in and out of this house, maybe the odd trip to the shops in the car when she’s out meeting the double agent. She mustn’t be suspected as being a part of this mission under any circumstances. So we need someone to pretend to be her, here at home, in case there’s any surveillance on us. It wouldn’t be dangerous in the least.’ Dad doesn’t say anything else. He just looks at me.

It doesn’t take me long to figure out what he means. ‘No way!’ I say at the same time as Mum says, ‘Certainly not!’

But Dad’s not listening to me – he’s turned to Mum. ‘Zelia, we discussed this. You can’t put yourself in that much danger without some protection.’

Mum laughs in a way that means she doesn’t think it’s funny. ‘We discussed it and I told you that if I’m not prepared to have some random spy who probably doesn’t even have her basic registration training impersonating me, I’m certainly not going to have Josie do it!’

It sounds like Mum thinks I wouldn’t be up to being her double! Obviously I’d do it brilliantly if I wanted to – I just don’t want to!

‘I don’t think you have a choice,’ Dad tells her, in his very rare I’m-not-going-to-change-my-mind-about-this voice. ‘And neither do you,’ he says to me.

‘It would stop your mum from being in danger,’ Sam says.

Thanks, Sam. Make me feel guilty about not wanting to pretend to be my own mother.

‘There’s got to be another way,’ I say.

‘Of course there’s another way,’ Mum says. ‘The idea is ridiculous.’

‘No,’ Dad tells us both, leaning forward. ‘It would work. And it would mean you won’t have a stranger in your house, Zelia. Besides, Joe’s already shown how good he is at taking on a different cover and who could know your mannerisms better?’

Typical. I’ve been trying to prove to Mum and Dad that I have good spy skills and as soon as I’ve done it they land me into trouble.

‘I’m not tall enough!’ I protest. I’ve got to put a stop to this plan before it gets out of hand.

‘You could wear high heels,’ Sam says. ‘You’re not that much shorter than your mum.’

‘Yes, it’s a good thing you’re petite, Zelia,’ Dad says. ‘That works nicely.’

‘Why don’t you do it?’ I ask Sam. ‘You’re a girl – that gives you a head start.’

‘But Sam doesn’t live with us, Josie,’ Dad points out. ‘She couldn’t be available at a moment’s notice.’

‘And my mum might notice if I kept disappearing,’ Sam points out.

‘I haven’t got … you know …’ I gesture at my chest. I don’t even want to say it.

‘Oh, a padded bra will take care of that.’ Dad waves his hand in the air.

I stare at him. Mum also stares at him.

For once, my mum and I are in complete agreement.

‘I suppose you’re going to teach Josie how to drive as well, are you?’ Mum says sharply.

‘Don’t be silly,’ Dad says. ‘I can do the driving when Josie’s being your double.’

‘She’s not going to be my double,’ Mum retorts.

‘Yeah,’ I say. ‘It’s hard enough being Josie, without being Josie’s mum as well.’

‘Anyway, it’s time to give you the details of your first collection,’ Mum says briskly. She keys in a few numbers on a Mission Control keypad and swivels to face us, shooting Dad one of her laser looks. I know what it means. It means Drop the subject, Jed.

‘But –’ Dad starts.

‘The first collection,’ Mum snaps. Her voice sounds like a crab clicking its claws.

Even Dad gets the hint. ‘Yes, your first collection,’ he says, hurrying over to the other side of the room, away from Mum.

They run us through the details and then Dad tells us we’re free to go. We’re heading off for a game of football when Dad calls after me.

‘What shoe size are you again, Josie?’

I frown at him. ‘Four and a half. Why?’

‘Oh, nothing!’ he says and waves me off, smiling.

I make a face at Mum that means Don’t Let Him Get Any Ideas About the Body Double Thing.

She makes a face back at me that means Don’t Worry, I Won’t Even Consider It.

Or at least I hope that’s what her expression means. Because there is NO WAY I’m going to agree to be my own mum.