It was my idea to go up the hill. I was trying to keep us as far from Ash House as possible, just in case, because otherwise, why wouldn’t a tour end up at the weirdest and most interesting place of all?

‘Let’s go up the hill and get cooler,’ I said. It was almost lunchtime by now, and roasting. Waves of heat rolled along the road. ‘The higher you go, the cooler it gets.’

‘Let’s not,’ Sam murmured to me.

‘It’ll be fine,’ I said. ‘It’ll be fun.’ Maybe Whizzy was making me more me, too.

‘Up to his house?’ asked Tombard, nodding at Sam.

‘No,’ Sam said quickly, blinking a lot. ‘Too many of us.’

‘Where then?’

‘Just up. Just higher,’ I said.

Sam shot looks at me. He was trying to say no without actually saying the word, but Tombard nodded and away we went.

I know all their names now. The big one is Matthew, the short one is Noel, and then there’s Kiran – another brown person besides me, yay!

‘Last one to Beggar’s Lane’s a piece of sewer grease!’ Tombard shouted, shoving Sam into Kiran. Seconds later, everyone was running up the hill with Tombard and Noel in the lead, Sam and Kiran next, and me and Matthew close behind, starting to overtake. Tombard screamed at the top of his voice like a mad witch, making us laugh till we went all weak. Then he swerved into Beggar’s Lane and we tore down the steep little drop with the breeze in our faces, dipping like seals, legs pumping automatically – we were nearly flying.

It was supernatural. Dizzying. The giddiness was like nothing I’ve ever known, like a giant was blowing bubbles and we were fizzing right at the top of them, laughing instead of breathing.

Still cackling, Tombard turned the corner into Bracken-bury Row and spilt into the allotments, legs splayed, out of control. Sam skidded to a halt. All the wildness left me and an uneasy feeling crept in. The air was virtually crackling with Whizzy’s power.

Sam’s told me about the allotments. It looks like a jumble of sheds and greenhouses and vegetable patches, but it’s him and his grandad’s special place.

‘Not here,’ Sam said, panting, and looking as hot as I felt. ‘My grandad might be here.’

The gang came to a juddering, gasping standstill, all of us even hotter and sweatier now we’d stopped running.

Tombard looked straight at Sam. ‘So?’

‘So we can’t,’ Sam said.

The others watched. Tombard let a little silence hang for a few seconds, then he said, ‘Can’t what?’

‘We can’t mess about,’ Sam said. ‘Not in here.’

‘Who can’t?’

Matthew kicked the ground impatiently and blew air out of his mouth in fast spurts.

‘Who can’t?’ Tombard repeated.