"Ali." Kasandra was good at knowing things that were hushed up by the government, especially considering that they had been, well, hushed up. They were always slightly occult. When giant footprints had appeared around the town centre during some snow last year there had been two theories. There was KiKasandra's, which was that it was Bigfoot, and Johnny's, which was that it was a combination of Bigmac and two "Giant Rubber Feet, A Wow at Parties!!!!" from the joke Emporium in Penny Street. KiKasandra"s theory had the backing of so many official sources in the books she'd read that it practically outweighed Johnny's, which was merely based on watching him do it.

Johnny thought about the Atlanteans, who'd all be two metres tall in Greek togas and golden hair, leaving the sinking continent in their amazing golden ships. And on the deck of one of them, Mrs Tachyon, ferociously wheeling her trolley.

Or you could imagine Attila the Hun's barbarians galloping across the plain and, in the middle of the line of horsemen, Mrs Tachyon on her trolley. Off her trolley, too.

"What happens", said Kasandra, "is that if you see a UFO or a yeti or something like that, you get a visit from the Men in Black. They drive around in big black cars and menace people who've seen strange things. They say they're working for the government but they're really working for the secret society that runs everything."

"How d'you know all this?"

"Everyone knows. It's a well-known fact. I've been waiting for something like this, ever since the mysterious rain of fish we had in September," said Kasandra.

"You mean, when there was that gas leak under the tropical fish shop?"

"Yes, we were told it was a leak under the tropical fish shop," said Kasandra darkly.

"What? Of course it was the gas leak! They found the shopkeeper's wig in the telephone wires in the High Street! Everyone had guppies in their gutters!"

"The two might have been coincidentally connected," said Kasandra reluctantly.

"And you still believe that those crop circles last year weren't made by Bigmac even though he swears they were?"

"All right, perhaps some of them might have been made by Bigmac, but who made the first ones, eh?"

"Bazza and Skazz, of course. They read about 'em in the paper and decided we should have some, too."

"They didn't necessarily make all of them."

Johnny sighed. As if life wasn't complicated enough, people had to set out to make it worse. It had been difficult enough before he'd heard about spontaneous combustion. You could be sitting peacefully in your chair, minding your own business, and next minute, whoosh, you were just a pair of shoes with smoke coming out. He'd taken to keeping a bucket of water in his bedroom for some weeks after reading about that.

And then there were all these programs about aliens swooping down on people and taking them away for serious medical examinations in their flying saucers. If you were captured and taken away by aliens, but then they messed around with your brain so you forgot about them and they had time travel, so they could put you back exactly where you were before they'd taken you away ... how would you know? It was a bit of a worry.

Kasandra seemed to think all this sort of thing was interesting, instead of some kind of a nuisance.

"Kasandra," he said.

"Yes? What?"

"I wish you'd go back to Kirsty."

"Horrible name. Sounds like someone who makes scones.

" ... I didn't mind Kimberly ... "

"Hah! I now realize that was a name with "trainee hairdresser" written all over it."

" ... although Klymenystra was a bit over the top."

"When was that?"

"About a fortnight ago."

"I was probably feeling a bit gothy at the time."

The bus pulled up at the end of Johnny's road, and they got off.

The garages were in a little cul-de-sac around the back of the houses. They weren't used much, at least for cars. Most of Grandad's neighbors parked in the street, so that they could enjoy complaining about stealing one another's parking spaces.

"You haven't even peeked in the bags?" said Kasandra, as Johnny fished in his pockets for the garage key.

"No. I mean, supposing they were full of old knickers or something?"

He pushed open the door.

The trolley was where he left it.

There was something odd about it that he couldn't quite put his finger on. It was clearly standing in the middle of the floor but managed to give the impression of moving very fast at the same time, as though it were a still frame from a movie.

Kasandra-formerly-Kirsty looked around.

"Bit of a dump," she said. "Why's that bike upside down over there?"

"It's mine," said Johnny. "It got a puncture yesterday. I haven't managed to repair it yet."

Kasandra picked up one of the jars of pickle from the bench. The label was sooty. She wiped it and turned it towards the light.

"Blackbury Preserves Ltd Gold-Medal Empire Brand Mustard Pickle"," she read. "Six Premier Awards. Grand Prix de Foire Internationale des Conichons Nancy 1933. Festival of Pickles, Manchester, 1929. Danzig Pokelnfest 1928. Supreme Prize, Michigan State Fair, 1933. Gold Medal, Madras, 1931. Bonza Feed Award, Sydney, 1932. Made from the Finest Ingredients." And then there's a picture of some sort of crazed street kid jumping about, and it says underneath, "Up In The Air Leaps Little Tim, Blackbury Pickles Have Bitten Him." Very clever. Well, they're pickles. So what?"

"They're from the old pickle factory," said Johnny. "It got blown up during the war. At the same time as Paradise Street. Pickles haven't been made here for more than fifty years!"

"Oh, no!" said Kasandra. "You don't mean ... we're in a town where no pickles are made? That's creepy, that is."

"You don't have to be sarcastic. It's just odd, was all I meant."

Kasandra shook the jar. Then she picked up another sooty jar of gherkins, which sloshed as she turned it over.

"They've kept well, then," she said.

"I tried one this morning," said Johnny. "It was nice and crunchy. And what about this?"

Out of his pocket came the newspaper that had wrapped Mrs Tachyon's fish and chips. He spread it out.

"It's an old newspaper," said Johnny. "I mean ... it's very old, but not old. That's all stuff about the Second World War. But ... it doesn't look old or feel old or smell old. It's ..."

"Yes, I know, it's probably one of those reprinted newspapers you can get for the day you were born, my father got me one for-"

"Wrapping fish and chips?" said Johnny.

"It's odd, I must admit," said Kasandra.

She turned and looked at him as though seeing him for the first time.

"I've waited years for something like this," she said. "Haven't you?"

"For something like Mrs Tachyon's trolley?"

"Try to pay attention, will you?"

"Sorry."

"Haven't you ever wondered what'd happen if a flying saucer landed in your garden? Or you found some sort of magical item that let you travel in time? Or some old cave with a wizard that'd been asleep for a thousand years?"

"Well, as a matter of fact I did once find an old cave with-"

"I've read books and books about that sort of thing, and they're full of unintelligent children who go around saying "gosh". They just drift along having an adventure, for goodness" sake. They never seem to think of it as any kind of opportunity. They're never prepared. Well, I am."

Johnny tried to imagine what'd happen if Kirsty was ever kidnapped by aliens. You'd probably end up with a galactic empire where everyone had sharp pencils and always carried a small torch in case of emergencies. Or they'd make a million robot copies who'd fly around the universe telling everyone not to be stupid and forcing them to be sensible.

"This is obviously something very odd," she said. "Possibly mystic. Possibly a time machine of some sort."

And that was the thing about her. She arrived at an explanation. She didn't mess around with uncertainty.

"Didn't you think that?" she said.

"A time machine? A time shopping trolley?"

"Well, what other explanation fits the facts? Apart from possibly she was kidnapped by aliens and brought here at the speed of light, which is something they do a lot for some reason. But there might be something else, I'm sure you've thought of it." She glanced at her watch. "No hurry," she added sarcastically. "Take your time."

"Well..."

"No rush."

"Well ... a time machined have flashing lights ..." "Why?"

"You've got to have flashing lights."

"What for?"

Johnny wasn't going to give in.

"To flash," he said.

"Really? Well, who says a time machine has to look like anything?" said Kasandra in a superior tone of voice, or at least an even more superior voice than the one she usually used. "Or has to be powered by electricity?"

"Yoless says you can't have time machines because everyone'd keep changing the future," said Johnny.

"Oh? So what's the alternative? How come she turned up with this new old newspaper and all these new old pickle jars?"

"All right, but I don't go leaping to great big conclusions!"

In fact he did. He knew he did. All the time. But there was something about the way Kasandra argued that automatically made you take the other side.

He waved a hand at the trolley.

"I mean," he said, "do you really think something could just press the ... oh, the handle, or the bags or something, and suddenly it's hello, Norman the Conqueror?"

He thumped his hand down on a black bag.

The world flashed in front of his eyes.

There was concrete under his feet, but there were no walls. At least, not much in the way of walls. They were one brick high.

A man cementing the new row looked up very slowly.

"Blimey," he said, "how did you get there?" Then he seemed to get a grip on himself. "Hey, that concrete's still Fred! You come here!"

A spaniel sitting by the man barked at Johnny and rushed forward, jumping up at Johnny and knocking him back against the trolley.