It wasn’t until the Japanese fishing boat picked me up the next morning that I realised how far I was from home.

I told the fishermen my name, and about what had happened, but that was obviously pointless because they didn’t speak English. I figured if I kept talking lots they might eventually work out what I was saying. They didn’t, but they did give me my own Japanese name and wrote it on a sign to wear around my neck! How cool is that? It looked like this:

Then when we got back to land, they couldn’t have been more helpful! I suggested that I stay with them for one more day, to sleep, but instead they drove me straight to the embassy and dumped me at the doors and drove off as fast as they could. They didn’t even want thanking!

The rest of the journey home was even better. When the embassy worked out who I was, everything changed. They put me in an amazing hotel room all by myself, with a Jacuzzi and a massive TV. It was brilliant, obviously, but to be honest it just reminded me of when Mum said we could go to the Hilton together, and that made me really miss her.

I couldn’t wait to see her again. I hoped she wasn’t too angry with me. She’d probably want to have a good shout and wave her arms a bit, but I figured that was fair enough.

After a few days, the embassy organised a private plane to take me back home – all the normal ones had been grounded after the Monster attack. That meant I was the only passenger on the flight, which meant I could lie down across five seats if I wanted to. And I did. The stewardess said if I needed anything then all I had to do was ask! So I asked for a Scotch on the rocks, and she said no.

We finally got back to the city, and as we flew over I couldn’t believe how different it looked. Now that the Monster had gone, all the water had drained away – but it had taken everything else with it. There were trees sticking out of buildings, and a tank on the clock tower, and whole streets covered in sand. There were sheep grazing on the runway when we landed.

And then when I stepped out of the plane, I got the biggest shock of all. There were hundreds of reporters and people with cameras waiting for me! They all went mad the second they saw me – waving posters with my face on them, and taking my picture, and asking me questions about the Monster and how I knew him.

But then I heard someone shouting over them, really loud. I turned around, and there she was at the front of the crowd.

‘… Mum?’

‘CAITLIN!’

She looked insane. Her hair was all over the place and her eyes were mad and her clothes were torn. I’d never seen her look at me like that before.

She leapt over the barrier to get to me. A soldier tried to stop her but she kicked him right in the nuts and kept running to me. I thought, Oh, this is it, I’m in trouble now … but then she fell to her knees and grabbed me tight against her so hard it was like she was trying to pull me into her. Everyone was cheering and clapping and taking pictures, but for a moment it was just the two of us. I couldn’t believe how much she was crying.

‘Oh Caitlin,’ she said quietly. ‘My wonderful girl.’

And then it didn’t matter where I was, because I was home already.

*

We couldn’t go back to Middle Island straight away. First of all lots of people in suits had to ask me questions about Perijee, and where he had come from and where he’d gone and how I’d found him. I gave them really good, extra-long answers, but for some reason this seemed to annoy them so eventually they let me go.

Then, of course, there was the big interview.

I sat in the visitors’ section of the dark studio and watched as the cameras turned on and the music started. The newsreader looked up.

‘Good evening,’ he said. ‘This is the news.’

It was the exact same presenter I’d seen talking to Dad just days ago – only since then he’d had his hair cut and dyed into a giant green Mohican.

‘Well, it’s been exactly one week since everyone thought it was the end of the world and made, er … some bad choices,’ he said, trying to flatten the Mohican and failing. ‘But we are still left with hundreds of unanswered questions about the Monster: who was he? Why did he disappear? And of course: will he ever come back?’

(On the screen behind him they played a shot of the ocean where I’d last seen Perijee, filled with boats and helicopters scanning the waves.)

‘Perhaps the strangest thing about the Monster is how little we still know about him,’ the newsreader continued. ‘In particular, where he came from. After a number of wildly incorrect theories about him arriving from space on a meteor have left some people’s reputations in tatters …’

(Cut to a shot of Dad’s convertible being publicly pelted with his own books.)

‘… and the members of the violent cults worshipping him have been locked away for good …’

(Cut to Mother and dozens of other soaking wet old ladies being piled into police vans, spitting at police officers.)

‘… we have to accept that the Monster might have come from somewhere else entirely. Here to discuss it with us is the leading world expert on deep-sea marine life: Dr Emily Williams.’

There was Mum, sat beside him. She was a bit nervous but she looked amazing. I’d never been more proud.

‘Go Mum!’ I cheered.

After the security guards had got me to stop cheering, they continued with the interview.

‘Dr Williams,’ said the newsreader, ‘perhaps you can tell us where the Monster came from?’

Mum coughed lightly.

‘Well, to be perfectly frank – no, I can’t,’ she said. ‘Because we still don’t know for certain. We do know that he comes from somewhere within the Mariana Trench – the deepest, most unexplored part of the world. The part we know the least about.’

The newsreader nodded. ‘So why did he come to the surface?’

‘Well, he first appeared after the meteor showers,’ Mum explained. ‘These caused extremely strong storms all across the world. So strong, perhaps, that they swept the Monster up from the bottom of the ocean floor and onto land by accident.’

The newsreader frowned. ‘But then … why did he wait so long to go back?’

Mum shrugged. ‘Well, perhaps that’s what those tentacles were searching for – a way back home. Maybe he could only go back when the time was right, or when the moon was causing the tides to fall in a certain pattern … who knows? We think that when one of his tentacles finally found the Trench, the rest of him just followed by instinct.’

I shifted on my chair. I had no idea if what Mum said was right or not. I was there when the Monster took Perijee home – it happened when he became happy again. Of course, it could have been a coincidence … like how Mother thought Perijee was the creature from the Prophecy, and he wasn’t – unless he was, of course, and the Prophecy hasn’t finished yet …

I shook my head. There was no point asking those kinds of questions right now. I looked at Mum, who was happier than I had ever seen her, and none of them seemed to matter.

‘So what you’re saying, Dr Williams,’ said the newsreader, leaning forwards, ‘is that we might not really know what there is on our own planet?’

Mum sighed.

‘There’s always something we don’t know anything about,’ she said. ‘More than we like to admit. The more we discover, the more we realise we don’t fully understand. Our world, our solar system, the universe … It all adds up. I mean, when you think about it – do we even know that much about ourselves?’

*

After her interview, Mum was probably more famous than the Queen. The next day she had calls and letters from universities all over the world, wanting her to start researching again. They even wanted her to go back to the Mariana Trench and lead the investigation into Perijee.

Mum said she’d get back to them, and put the phone down. Then we went out and spent the day together – just the two of us.

*

They put me and Mum on a train heading back home. Not just any train – we had our own carriage, with beds and a kitchen and everything! It turns out that when you become friends with an alien that tries to take over the world, everyone’s really nice to you.

The next morning I walked into our private dining carriage, and there was someone else sitting at the table. I couldn’t believe my eyes.

‘Frank!’ I cried.

‘All right, sprat!’

He was looking really good – wearing shoes and everything. I gave him a hug.

‘What are you doing here?’

‘Your mum invited me!’ He gave her a sheepish look. ‘Which was very kind of her, seeing as, er … seeing as I’m not her favourite person at the moment.’

Mum gave Frank a dark look.

‘He’s not?’ I said.

‘Well, no, Caitlin,’ said Mum. ‘He put your life in danger. He let you climb onto an alien’s back and get carried to the other side of the world.’

‘He wasn’t an alien,’ I pointed out. ‘Remember? He was a “subterranean megabeast”.’

‘Whatever,’ said Mum. ‘Either way, Frank’s lucky I haven’t killed him.’

She scowled at him again, then smiled.

‘That said, if he hadn’t gone after you like he did …’

Frank shrugged, but couldn’t hide how much he was blushing. I looked at them both, confused. She was angry, but she wasn’t. Adults never make any sense.

‘So … what are you doing here?’ I asked Frank.

Frank coughed. ‘Your mum said something about a plan, sprat. Something she wants to talk to both of us about.’

We looked at Mum expectantly. She shuffled on her chair.

‘Er … yes,’ she said. ‘But before I get into all that, first of all I should say … well, even though you should never run away like that again, Caitlin, and if I ever find you trying to raise another alien …’

‘Subterranean megabeast,’ I corrected.

‘Yes, well.’ Mum sighed. ‘What I’m trying to say is … I know I’m not free from blame for what happened.’ She held my hand. ‘I mean, if I’d actually listened to you, Caitlin – if I’d spent more time with you on the island, known you a bit better, understood how unhappy you were at school, how lonely you were, and how much Perijee meant to you … maybe none of this would have happened. At the time I was too sad to see what was wrong with everything … but that doesn’t make it OK. I’m so sorry, Caitlin. I really am.’

She gave my hand a squeeze. I smiled.

‘It’s fine, Mum.’ I meant it, too.

‘No it’s not,’ said Mum. ‘That’s why I don’t want anything to go back to the way it was.’

My face fell. ‘… You don’t?’

‘No,’ Mum smiled. ‘I want it to be much better. I want to rebuild Middle Island. Not just our house – lots of houses. Maybe even a school, seeing as the Monster squashed your last one.’

I gasped. ‘You mean we’ll have neighbours?’

Mum nodded. ‘Neighbours, pets … we’ll have them all!’

She held hands with me and Frank.

‘That’s why I wanted Frank here today – and every day after that. He’s going to help us do it. Because sometimes family isn’t enough. You need friends too. Good people. You need to have them around you all the time, even if you can’t see them …’

Suddenly the ceiling caved in and something landed in the middle of the table in a cloud of dust and foam insulation.

*

Fi apologised for sneaking into our air ducts at the station and for ruining our breakfast, but she explained that her cow-rustling had made her one of the most wanted criminals in the country and it was the only way she could get on board. She also said that a village on Middle Island sounded like a great idea, and that we could borrow her boat to transport stuff over from the mainland if we wanted, so long as we paid her an upfront deposit and a weekly rent thereafter, and so long as Mum adopted her.

Mum took a lot of convincing – partly because she didn’t like the terms of the deal, but mainly because she had no idea who Fi was – but in the end, me and Frank talked her round.

‘Fi’s the smartest person I know!’ I said. ‘She can trick a whole roomful of people. Plus, she could tell that Mother actually wanted to sacrifice me.’

Mum frowned. ‘Sacrifice? Caitlin, what on Earth are you …’

‘And she’s going to teach me to read, too!’ I said. ‘Please can you adopt her, Mum? Please please please?’

Mum didn’t look too convinced. Frank put a hand on her shoulder.

‘Emily – look, I know she seems like a sneaky little thief …’

‘Oi,’ said Fi.

‘But she’s a good person,’ said Frank. ‘She gave up everything she had to help Caitlin. She really does love her, you know.’

I beamed. ‘That’s right! We’re friends.’

‘Best friends,’ said Fi.

*

We decided to celebrate our last night on the train before we got back to Middle Island. Frank bought a bottle of champagne and we all had some (even me!) and then I got dizzy and had to lie down. Mum did a dance and we managed to convince Frank to take his eye out. Fi showed us all how to pickpocket someone properly, but then Frank realised the wallet she was using was the one she’d stolen off him at the meeting, and Fi apologised and promised that from now on she was never going to steal anything ever again, but to be honest it was his own fault for keeping it in his back pocket anyway, and they were still arguing about it when I went to bed.

Actually, I didn’t really go to bed. There was something that I wanted to do first. I made my way to the engineers’ carriage, opened the hatch on the ceiling and climbed out onto the train roof.

Mum would have killed me if she knew – but then she doesn’t need to know everything I do. I can do loads more than she thinks I can. That’s what’s different about me and Mum – she’s amazing at the thinking side of things, which I’m not so great at. But I’m really good at doing.

I lay down on the carriage roof and looked up at the stars as the night slipped past. I love looking at them more than anything. I reckon it’s where I do my best thinking – and I had lots to think about that night. I thought about how great it was that I suddenly had a whole family out of nowhere, and the best friends I could ever have asked for. I thought about how lucky I was.

And I thought about Perijee, of course. How could I not? I lay back and thought, He’s out there somewhere – under the ocean, where I can’t see him. Which sounds sad in some ways, but it’s not really. Just because I can’t see the bottom of the ocean, it doesn’t mean it’s not there. It’s just hills and valleys covered in water.

I wondered where Perijee had ended up, and what was waiting for him back at his home. Maybe there were hundreds of other creatures like him down there – a family of his own, worried sick about him and wondering where he’d gone. Of course, I didn’t know for sure – and I might never find out.

It’s like the stars. You look up on any night and there’s all of space, right ahead of you. Who knows what’s out there that you can’t see – there could be millions more Perijees, and billions of planets we’ve never seen, and trillions of people we haven’t met, all dotted throughout the universe and looking back at the stars and wondering.

Which is a nice way to think about something that’s normally a bit scary, isn’t it? Space is the biggest thing you can imagine. It’s so big and empty that it’s easy to feel lonely when you look at it.

But I don’t feel lonely when I look at it – not any more. Because no matter where I am, or where I go, or what I do, I know that there are people I love out there who are thinking of me.

And as for Perijee – well, I’m always thinking about him, too. There’s not a single day that goes past where I don’t miss him, and hope he’s happy.

Otherwise, what’s the point of being a friend?