I’m going to be like Sherlock Holmes tracking Moriarty. This is going to take meticulous planning – even more than when I recreated the town hall from lollipop sticks. I take a piece of paper from my desk and write:

DANIEL GEORGE HOPE

AGE 11

OPERATION BASKERVILLE

(You have to use names like Baskerville because that way no one really knows what you’re up to. If I wrote Operation Meeting Dad then Ninja Grace would be onto me like a bloodhound.)

The very first job of Operation Baskerville is to find Dad’s address.

Thirty minutes and one very messy hallway later and I’ve found this ancient book that appears to have all the addresses of local people inside it. Yes, the actual addresses plus phone numbers. The thing weighs as much as a brick and when Mum asks me why I’m carrying the telephone directory up to my bedroom I tell her I’m going to stand on it so I can reach something at the back of my cupboard.

“Really?” Mum arches her eyebrow. “I’m surprised you can open your cupboard without an avalanche falling on your head. Well, when you’ve finished whatever mischief you’re up to, I have an idea. Look up cleaners in the directory. I need someone to tidy this hallway. I think you’ll find the person under H for Hope. First name: Daniel.”

There are three people in the directory with the same name as Dad: Malcolm John Maynard. Dad doesn’t have the same surname as us because Mum made sure we took her name, which I guess is kind of lucky now. Pulling out my mobile, I ring Malcolm J. Maynard number one. He says, “Wrong number, mate,” and then hangs up. The second one sounds faintly Scottish and calls me “bairn”, even though I tell him three times that my name is Dan. The third tells me he’s always getting phone calls for that new TV presenter and everyone is really getting on his goat. His goat must be the size of the biggest Billy Goat Gruff if everyone is getting on it. In the end I hang up, because I have no leads and I have to tidy the hallway.

The whole of Operation Baskerville is in jeopardy until Big Dave makes me think otherwise. He appears on the dot of six and says he could eat a scabby dog. Mum tells him it would be wrong to eat Charles Scallybones the First so perhaps we should have a takeaway instead. Now, this is hardly riveting and has nothing whatsoever to do with Operation Baskerville, but what Big Dave says next does. Chippy chips are what Big Dave wants, from The Frying Squad to be precise. Mum says she’s not eating from a place where girls wear the scent of cheap malt vinegar.

“Wok This Way it is then,” says Big Dave. “The man behind the counter can lure me with a number twenty-five and the scent of sweet ’n’ sour chicken balls instead.”

And, thanks to Big Dave’s chicken balls, I know exactly where to find Dad’s address.

“So…how’s it going with the medal?” whispers Jo, looking down at her list of fractions. “Do you still feel sad?”

“I never told you I felt sad in the first place,” I whisper. “What’s the answer to 1/7 x 1/8?”

“You didn’t need to tell me, it was written all over your face.”

“What, in invisible ink?” I mutter. “Is it 1/56?”

“Yes. That medal will change your life,” replies Jo. “Saint Gabriel always gets results. That’s what my grandma said.”

“Before she died, yes,” I hiss. “What’s the answer to 41/3 + 41/3?”

“Grandma might have died but that wasn’t the end of it. She sent me a feather, you know.” Jo looks at me. “A message from her was on my list of ten things and it arrived after her funeral. Feathers are angels’ calling cards. It means the dead person is up there and looking after you and they’re sending you a white feather to let you know that everything will be okay.”

“Jo, I hate to break this to you, but feathers come from birds’ bums.”

“The answer is 82/3.” Jo scribbles on her test sheet and turns away from me.

“Class,” says Mrs Parfitt, “I’d like to add an extra verbal question to your test. Answer this: a group of Year Six students were working on their maths test. Their teacher noted that 3/7 were writing down the answers like good children, 2/7 were trying to figure out the answers but this involved them staring out the window, and 1/7 were looking at the clock and wishing it was over. And one person was chattering away in the middle of a test and distracting everyone else. What was the name of that one person?” Mrs Parfitt’s hand bangs on my desk. I’ve never seen her hands close up before. Her knuckles resemble an elephant’s knees.

A few people start scribbling down my name and laughing.

“Daniel Hope,” she says, pointing to my test paper. “If you don’t stop these cosy chats with Jo and work out the answers yourself, what score do you think you’ll be getting on this paper?”

“Zero,” I reply.

“Correct,” Mrs Parfitt replies.

The whole matter would have been closed with Mrs Parfitt’s telling-off, only I look over at Christopher and he glances up at me and then Jo. For a split second he seems embarrassed, but that’s not all. Christopher also looks a bit smug, as if I deserved a telling-off for talking to Jo. But that doesn’t even make sense.

At morning break I’m standing by the toilet block when Christopher walks past and throws a tennis ball against the wall. When it bounces I snap it up and hand it over to him, saying, “You were good at tae kwon do. Sorry I couldn’t hang around and watch for longer but I had my dog with me.”

Christopher nods but doesn’t answer.

“Have I done something else to annoy you?”

“No,” he replies.

“Is this about Jo? You looked sort of happy that I got into trouble because we were talking. But it’s not my fault that Jo keeps jabbering on about religious relics and feathers that come from angels’ bums.”

Christopher bounces the tennis ball up and down, then stops and looks across at Jo.

She’s slouched on a bench, with long copper waves of hair falling down past her shoulder. One sock is up and the other down and she’s playing with a badge on her blazer lapel. When she senses Christopher and me looking at her, she waves. Christopher smiles back and does this ridiculous little micro finger-wave that makes him look about two.

“Hey,” shouts Christopher, “come and talk to me.”

Jo pulls up her sock, wanders towards us and then asks me if I want to come round to her house after school.

I shake my head. “I’m busy with Baskerville.”

Jo’s eyes widen. “What’s that?”

I shrug and say I could tell her but then I’d have to kill her. Jo laughs and informs me that I’m missing out. She has a new plastic statue of the Virgin Mary that I’ve really got to see. When you switch the lights off her heart glows in the dark and if you wind up her halo she plays “Ave Maria”.

“I’d like to see it,” says Christopher.

And that’s when I know for certain what Christopher’s problem is.