Look: put yourself in my shoes.

It’s been nearly a week now and the truth is, I’m not even sure whether to believe what the letter says. Would you?

And I’m thinking about this – what we believe and everything – when something occurs to me that sort of tips the balance in my indecision. (Indecision, by the way, which is now so bad and so distracting that last night I hardly slept at all and my form teacher, Miss Henry, kept me back after school for one of those, “Is everything all right with you?” chats.)

You see, my mum believes in ghosts, even though she told me there’s no such thing.

I’ve started to think about it now because of the letter from my dad and because I’ve been thinking about it, I’ve remembered this stuff from a book I tried to read called 2001: A Space Odyssey, which everyone thinks is just a film, but it’s actually a book as well, and the writer predicted loads of stuff long before it ever happened, like the satellites that let us use mobile phones, and men visiting the moon.

Anyway, in 2001 he said that, “behind every man now alive stand thirty ghosts.” Now, by ‘man’ he meant ‘person’, because that’s how people wrote back then, and the ghosts thing just meant that for every person then alive, thirty people had died in history.

He wrote that in 1968 when the world’s population was about half of what it is now. If he was writing it now, it would be ‘behind every person now alive stand fifteen ghosts’.

That means that more than 100 billion people have died on earth since humans began, which is funny because that’s the number of stars in the Milky Way, according to my dad.

I don’t think Arthur C Clarke, who wrote it, believed in ghosts – I mean, actual proper ghosts like you get in stories, the kind that haunt places. Dad didn’t either – he told me so. Actually, what he said was that he thought it was ‘stupendously unlikely’. That’s what he used to say about things that he thought weren’t real, but that no one could prove.

Stupendously unlikely. It’s a cool phrase.

Like, you can’t prove that ghosts don’t exist, can you? All you can say is that it’s stupendously unlikely.

Mum wasn’t so cautious, though. I had a bad dream once when I was little, and I thought there was a ghost living in the loft and she told me – definitely and certainly – that there was no such thing as ghosts; that it was all just our imaginations.

So I grew up not believing in ghosts. Stuff like Scooby Doo was good fun and I got really scared one Christmas by a ghost in a play, but I knew it wasn’t real.

But after Dad died, Mum changed.

It wasn’t long after he had died, maybe a month, and I overheard Mum talking to Aunty Ellie. We were still living in Chesterton Road in Culvercot then. I couldn’t sleep so I had got up to get a glass of water and I heard them talking in the front room and I stayed to listen on the stairs.

“Come on, Sarah,” Aunty Ellie was saying, sort of soothing.

“No, I did, Ellie, I did, plain as day. He was standing right there. The funeral director was sitting where you’re sitting, and he came through the door, and sort of looked at me, and looked at Dennis Harrison and his mouth went ‘no!’ and he went out the door as quiet as anything.”

“What did you do?”

“Well, I was in a daze. I just stared, and Dennis Harrison saw me gaping at the door, and he asked me, ‘What’s the matter?’ and I said, ‘I’ve just seen Pye!’ and he just nodded. ‘A lot of people say that,’ he said.”

“And that was it?”

“That was it. He didn’t look like a ghost or anything.”

“What was he wearing?”

“Like, did he have a sheet on him? No, Ellie, he was wearing his normal stuff. His jeans, his blue cotton check shirt, you know? The one he liked.”

“Listen, honey, it’s a very stressful time, I think—”

“Ellie, don’t tell me I was imagining it. It was real, he was there. Right there!”

“I’m sure he was.”

“And don’t patronise me either.”

They stopped talking for a minute, then I heard, “Al? Is that you?”

But by the time Mum came out to check, I was back in bed.

I still don’t believe in ghosts. But what if Mum hadn’t seen a ‘ghost’?

What if she had really seen Dad, only that Dad was a ‘ghost’ from the past? In other words, what if Dad had travelled from a time before he was dead to a time after he was dead, and accidentally turned up while his own funeral was being planned?

I know. Stupendously unlikely. But it all pushes me further towards the decision I know I have to make, even though I still don’t know how I’m going to get from Blyth to Culvercot at night.

I’m going to do it. I’m going to follow my dad’s instructions, and travel in time.

I’m not sure it’s a good idea.

I’m still not.