‘We can’t go back down there yet and I’m starving,’ Tam says. ‘Catrin? Fancy helping me make a fire? The twigs in here look dry enough.’

She acts like she hasn’t heard him.

‘Catrin?’ he says again, looking confused. ‘What’s up with you?’

‘What’s up with me?’ She turns on him. ‘What’s up with you, more like! Why didn’t you help Jason?’

‘What?’

‘You! You could have forced Gary and Dean to fetch his sleeping bag. But, no, you just had to stand there like a big lemon being all No need for any aggro. Well, maybe we needed aggro! Maybe aggro is all they understand!’

Me and Jinx watch them, as though we’re hypnotised.

Tam concentrates on building a little wigwam around some scrunched-up paper. ‘Like my father says, violence isn’t the answer.’

Sometimes I reckon he doesn’t have any thoughts that don’t come from his father, but I’m not getting in the middle of this.

‘If you didn’t want to hit them, you should have tried to get into the Copperworks,’ Catrin rages.

He sighs. ‘Even without the giant man and his rabid dog, did you see all the danger signs? You know what happened with the bull!’

She shrugs. ‘Survived that though, didn’t you?’

He says nothing.

‘Oh, forget it!’ She holds her hand out to Jinx. ‘Toilet roll, please. I’m going for a wee.’

He passes it to her and she stamps off into the bushes. Jinx looks to me and does a long, low whistle. He’s finally getting to know the real Catrin and I think he’s impressed.

Ten minutes later, the smell of warm baked beans fills the cave. Tam hands round spoons and enamel plates, then scoops the beans out.

‘Well, this is nice,’ Jinx says, like he’s an old woman, and the rest of us laugh – even Catrin. Sometimes the funniest thing about Jinx is that he doesn’t know he’s funny.

When we’re all scraping our plates, I sit up and declare, ‘Beans, beans, they’re good for your heart …’ I look around, waiting for them to join in. They all do:

‘The more you eat, the more you fart …’

‘The more you fart the better you feel …’

‘So eat your beans with every meal!’

We say it over and over, getting more and more daft, finding it funnier than it actually is.

Then Tam really does let one go and it echoes round the cave. Jinx asks if he needs paper or stitches, Catrin snorts, and I’m laughing so much I’m in actual pain.

‘We need to go,’ I splutter.

It takes another five minutes to properly calm down, pack up and get going.

The side of the mountain is so steep we have to grab on to branches as we go. Near the bottom, Jinx slips and tries to turn it into a commando roll but he looks more like a giant, floppy sausage.

Back on the river path, Tam asks, ‘How far now, do you reckon?’

‘We’ll be there before it’s dark,’ Jinx says. ‘And I’ve had an idea of somewhere better to stay.’

‘Where?’ I ask.

He taps the side of his nose. ‘All you need to know, Jason, my friend, is that there’s no hay.’

‘Funny guy.’

About half an hour on, something breaks under my foot with a snap and a crunch. It feels weird, and too brittle to be twigs. On the ground, next to some old fencing, is a little pile of broken bones.

‘You all right, Jase?’ Tam asks.

‘Yeah.’ I bend down and hold back a patch of ferns. ‘Just stood on these.’

He comes for a closer look. ‘What are they?’

‘Some sort of animal bones. A rabbit or a weasel maybe. Quite small anyway.’

Catrin and Jinx look too. She lifts up the skull, which is still in one piece. ‘Look at the fangs on it!’

We pass it round. Tam folds his arms, refusing to touch it. Jinx makes out like he knows all about skeletons and starts to tell us useless facts about bones. Me and Tam pretend to fall asleep and make loud, snoring noises.

‘Don’t be mean,’ Catrin says, but she’s giggling.

‘Anyway,’ Jinx says, twyting down to inspect the broken pieces. ‘I do know something about bones you’ll be interested in.’

‘I doubt it,’ Tam mumbles, letting out a massive snorty snore.

Jinx ignores him. ‘In Llanbryn, some kids found a human skull in a tree once.’

I open my eyes. ‘Serious?’

‘Yeah, my grandad told me. It was in the war.’

‘What happened?’ Tam asks. ‘Whose skull was it? Was it a murder?’

Jinx screws his face up. ‘I can’t remember, but Grandad said it was a really big deal in the village.’

‘Fascinating story,’ Tam yawns again. ‘You should be on Jackanory.’

‘Well, I’m glad I didn’t stand on human bones,’ I say, doing a big, on-purpose shudder.

Catrin passes the skull back to Jinx. ‘Think the Beast could have killed this animal?’

‘Nah,’ he says. ‘We’re too far from Blaengarw. But whatever it was wasn’t put off by these fangs.’ He jigs the skull about near Catrin’s face and makes growling noises.

She bats his hand away, giggling again.

‘How far is it?’ I ask. ‘In miles.’

‘About five, I reckon. We’ll get on the right side of the river at the stepping stones – won’t be far from there.’