There must be MILLIONS of these things, thought Dot. How are we EVER going to find the one that’s the Wisp of my Mr Mouse?

Well, it may not have been millions, but it certainly looked like it from the doorway where they all stood.

“Hic!” said Wiz, as Buzby continue to flutter round inside his tummy. “This looks IMPOSSIBLE!”

All around them, and above, floating in the air inside the tent as high and as far as they could see, were computer mouse shapes. They were bathed in the cerulean blue light of the colony, and bobbed gently up and down. There was a kind of corridor in the middle of the Wisps.

When you got close, you saw they were see-through, which made it even harder to tell how many there were exactly – the rows and rows of them stretched away all round Dot and her friends, above them, to the side, off into the distance.

“Reset MiniTracs for in-colony find!” said Walpurgis. Each of the TricTrucTrackers brought their squidgy little devices near to their beaks, and started humming to them – all different tunes, but somehow blending with each other.

Big as the Colony Cerulean tent had looked from the outside, inside it was even bigger. Peer as she might through her glasses, Dot couldn’t make out where the tent ended.

But it reminded her of something. Oh yes! That time she and her Mum and Dad had been in a lift at one those posh hotels – a lift with mirrors on both sides. When you looked into it you saw image after image of yourself vanishing into the distance, because each mirror reflected the other, and you in it. It was weird – the reflections just went on and on as if they were going miles away, getting smaller and smaller.

“Vairy strange!” said Fromage, from his favourite spot on top of Dot’s left shoulder. He lent forward to the Wisp nearest to him – Dot suddenly noticed how they’d gently been closing up around them, though a narrow corridor was still clear – and gave it a tap with his mousey little claw.

Or tried to! As his claw came near, the Wisp moved away – and so did the one next to it, and the one after that. It was like a shoal of fish turning together because a dangerous fish like a shark was approaching.

The TricTrucTrackers’ humming stopped. “Excellent!” said Walpurgis. “Now we can begin! Set MiniTracs to - ” he looked down at a little gadget like a watch on his wrist, and gave it a shake – “Hyphenmarc 650R!” He smiled at Dot. “That’s your friend’s cybermark, remember?”

“Oh, yes” said Dot. (You didn’t really Dot, but never mind!!)

“OK everyone!” said Walpurgis. “Let’s track! Usual sectors!”

To Dot’s amazement – but with more humming, which should have warned her – each of the TricTrucTrackers, one by one, rose up in the air, with the Wisps bumping gently against them.

As she watched, they slowly move apart and disappeared among the thousands of mouse-like shapes – till only she, Fromage and Wiz where left on the ground, with Walpurgis. He gave them an encouraging smile.

“Don’t worry!” he said. “They’ll be back! But to get the kind of detail we need, we have to get our MiniTracs as close as possible. Hop in!”

With a “zeeeet!” noise a twin chair folded out of the back of his backpack.

“Hop up!” he said. “Haven’t got all day!”

“But… how?” asked Dot. It didn’t look possible – and anyway surely she’d be too heavy.

“Easy!” said Walpurgis over his shoulder. “Just make sure your friends are with you” – still unsure, Dot tucked Wizard under arm, and Fromage tucked himself under the corner of the shoulder of her T-shirt “and THINK yourself into my courtesy carrier!”

So, still doubting, she did (eyes fast shut!)

And to her amazement she felt herself lift gently up, then fall back into the courtesy carrier. She opened her eyes.

“All set?” asked Walpurgis.

“Er… yes!” said Dot.

“Well then let’s go mouse-hunting!”