When I told Grandpa about the letter, he huffed and cleared his throat a lot, and then agreed that I had to go.

“Adventuring is more important than anything,” he said.

“This might be the Adventure that takes me to Mum and Dad!” I said, shovelling stuffed peppers into my mouth and trying not to think about what they were stuffed with.

“I’ll make you a packed lunch,” said Grandpa, and my stomach gave an apprehensive lurch. “You can’t go on an Adventure without supplies!”

I scooted upstairs and stuffed everything that I thought I might need into my backpack. After all the things that have happened to me, I’m getting pretty good at packing fast. My Adventure kit consisted of:

• Stun gun (in case of woolly mammoths)
• Morph’s memory chips
• Omnilume
• Tranquillizer darts (still thinking about those woolly mammoths)
• Night-vision goggles
• Camouflage paint for hiding from anything large and woolly
• Grandpa’s spy diary
• Compass that always points to home

My amulet was already hanging around my neck. I had found it inside one of the letters, and it had helped me out of danger more than once. I would never go on an Adventure without it.

My bedroom door banged open against the wall and Grandpa strode in. His Westie, Plato, was scampering around his ankles like a fluffy white blur, yapping eagerly. Seconds later I realized why. The peculiar aroma coming from the box in Grandpa’s arms would have stopped an army. It certainly smelled like a dog’s dinner, so you couldn’t blame Plato for being excited.

Grandpa thrust the enormous box into my arms and I held my breath. I pulled off the lid and peered down at a packed lunch that even Rex would have thought twice about eating. I know Grandpa’s a bit eccentric. OK, a LOT eccentric. But this time he had outdone himself.

“Beef ice cream?” I said. “Are you sure about this, Grandpa?” I lifted one of the sandwiches and sniffed it without getting too close. “Orange and mustard?”

“Delicious,” said Grandpa, licking his lips. “And you’ll really enjoy the salad surprise.”

“Jellied kippers, peanut butter and chocolate sausages – they look awesome – what’s this?” I held up a muddy liquid.

“Energy drink, Philip,” said Grandpa Monty. “My own recipe! Cold cocoa, three raw eggs, five shots of coffee, a dash of cod-liver oil and plenty of pepper.”

I made a mental note never to open that bottle. Grandpa ushered me into Morph. Now he’d made up his mind that I should go, he seemed very keen for me to get started.

“Good luck!” he called as he pulled the door shut.

At once the time machine sprang into life. Morph seemed to know where to take me on my next Adventure, because I didn’t have to do a thing. The air around me shimmered with light and the electricity crackling all around me made the hairs on my arms stand straight up. I squeezed my eyes shut and felt the time machine begin to spin.

Suddenly my stomach gave a sickening lurch. I had left my backpack on the floor of my bedroom! My Adventure kit had been left behind!

My eyes flicked open but I squeezed them shut again immediately – the light was unbearable.

“Stop!” I hollered, banging my fists blindly against Morph’s door. “Go back!”

But Morph had no intention of stopping. We dropped, and my stomach felt as if it were in an elevator that had just been cut loose. I couldn’t tell if I was up, down, spinning or still, and I stopped worrying about the backpack and started concentrating on not throwing up.

Morph stopped moving, and about ten seconds later my head stopped spinning. That was one rough ride. I staggered to my feet and thought for a minute. I had no warm clothes, no Adventure kit and no computer chips, which meant that Morph would have to stay as a time machine for this Adventure. What was I going to do?

I patted my pockets and looked around. I didn’t have much to help me.

• My SurfM8, which had no signal
• A mega-weird packed lunch

The boy was a bit shorter than me, but he had seriously muscly arms and legs. His face was small and wide, with heavy brows, and he was wearing an animal skin draped over one shoulder. His black hair was matted and stuck out all around his head, just like Grandpa’s. He lifted one grimy, stubby finger and pointed it at me.

Just then, I felt the amulet around my neck getting warmer and warmer. When I visited ancient Egypt the amulet had helped me to understand a foreign language. Maybe it would do the same again.

“Hi!” I said. “I’m Will. I’m just . . . er . . . visiting.”

It was mega-weird. The words coming out of my mouth were just grunts and snorts – it sounded like I had the worst cold ever.

“Uh,” he said. “Um.”

There was definitely something wrong, but I had no idea how to fix it. I pressed the hot amulet harder against my skin. Why wasn’t it translating for me?