"I don't like lying."

"Are you going to tell her the truth?"

Yoless thought for a few agonized seconds. "Your phone was broken, right?"

"Yeah, and I'll tell my mum I was staying at your place," said Wobbler.

"I shouldn't think my grandad's noticed I'm not in," said Johnny. "He always drops off in front of the telly.,

"My parents have a very modern outlook," said Kirsty.

"My brother doesn't mind where I am so long as the police don't come round," said Bigmac.

Before time travelling to any extent, Johnny thought, you should always get your alibi sorted out.

He stared at the place where Paradise Street had been. It was still the Sports Centre. That hadn't changed. But Paradise Street was still there, underneath. Not underground. Just ... somewhere else. Another fossil.

"Did we change anything?" said Kirsty.

"Well, I'm back," said Wobbler. "And that's good enough for me."

"But those people are alive when they ought to've been dead" Kirsty began, and stopped when she saw Johnny's expression. "All right, not exactly ought, but you know what I mean. One of them might've invented the Z-bomb or something."

"What's the Z-bomb?" said Bigmac.

"How should I know? It wasn't invented when we left!"

"Someone in Paradise Street invented a bomb?" said Johnny.

"Well, all right, not a bomb. Something else that'd change history. Any little thing. And you know we left all Bigmac's stuff in the police station?"

"Ahem."

Yoless removed his hat and produced a watch and a Walkman.

"The sergeant was so flustered he forgot to lock the cupboard after he got the siren out," said Yoless. "So I nipped in."

"Did you get the jacket?"

"Chucked it in a dustbin."

"That was mine," said Bigmac reproachfully.

"Well, maybe that's all right," Kirsty conceded reluctantly. "But There's bound to be some other changes. We'd better find out pretty fast."

"We'd better have a bath, too," said Wobbler.

"Your hands have got blood on them," said Johnny.

Wobbler looked down vaguely.

"Oh, yeah. Well ... we were pulling at smashedup walls and things," he said. "You know ... in case there was anyone trapped ... "

"You should've seen him grab his grandad!" said Bigmac. "It was brilliant!"

Wobbler looked proud.

They met up an hour later in the mall. The burger bar was back to the way it had always been. No-one said anything about it, but from the way he sighed occasionally it was clear that Bigmac was thinking of free burgers every week for the rest of his life.

That jogged Johnny's memory.

"Oh ... yes," said Johnny. "Er. We've got this letter ... for you ... "

He pulled it out. It was crumpled, and covered in vinegar and sooty fingerprints.

"Er, It's for you," he repeated. "Someone ... asked us to give it to you.

"Yeah, someone," said Yoless.

"Who we don't know who he was," said Bigmac. "A completely mysterious person. So It's no use you asking us questions."

Wobbler gave them a suspicious look, and ripped open the envelope.

"Go on, what's he say?" said Bigmac.

"Who?" said Wobbler.

"Y- this mysterious person," said Bigmac.

"Dumb stuff," said Wobbler. "Read it yourself."

Johnny took the paper that had been in the envelope. It contained a list, numbered from one to ten.

"1) I Eat healthy food in moderation", he read. "2) An hour's exercise every day is essential. 3) Invest money wisely in a mixture of-"

"What's the point of all this junk? It's the sort of thing grandads say," said Wobbler. "Why'd anyone want to tell me that? You'd have to be some kind of loony to go around telling people that. This was one of those religious blokes that hang around in the mall, right? Huh. I thought it might be something important."

Bigmac glanced at the burger bar again, and sighed deeply.

"There have been changes," said Kirsty. "Clark Street isn't Clark Street any more. I noticed when I went past. It's Evershott Street."

"That's frightening," said Bigmac. "Oooeeeoooeee ... a street name was mysteriously changed ... "

"I thought it was always Evershott Street," said Yoless.

"Me too," said Wobbler.

"And that shop over there ... that used to sell cards and things. Now It's a jeweler's," said Kirsty insistently.

The boys craned around to look at it.

"It's always been a jeweler's, hasn't it?" said Wobbler. He yawned.

"Well, You're an unobservant bunch, I-" Kirsty began.

"Hold on," said Johnny. "How did you get all those cuts on your hands, Wobbler? You too, Bigmac."

"Well, er, I ... er ... " Wobbler's eyes glazed.

"We ... were messing around," said Bigmac. "Weren't we?"

"Yeah. Messing around. Somewhere."

"Don't you remember-?" Kirsty began.

"Forget about it," said Johnny. "Come on, Kirsty, We've got to go."

"Where to?"

"Visiting time. We've got to see Mrs Tachyon."

Kirsty waved a hand frantically at the other three.

"But they don't seem to-"

"It doesn't matter! Come on!"

"They can't just forget!" said Kirsty, as they hurried out of the mall. "They can't just think: "Oh, it was all a dream"!"

"I think It's all sort of healing over," said Johnny. "Didn't you see it happening back in 1941? Tom didn't really believe anything that had happened. I bet by now ... I mean, a few hours after ... I bet They're remembering ... I mean, they remembered ... something different. He ran all the way and got there just in time. Everyone was a bit shocked because of the bombing. Something like that. People have to forget what really happened because ... well, it didn't happen. Not here."

"We can remember what really happened," said Kirsty.

"Perhaps that's because You're hyper-intelligent and I'm mega-stupid," said Johnny.

"Oh, I wouldn't say that," said Kirsty. "You're being a bit unfair."

"Oh. Good."

"I meant I wouldn't go so far as to say "hyper". Just "very". Why do we have to see Mrs Tachyon?"

"Someone ought to. She's a time-bag-lady," said Johnny. "I think It's all the same to her. Round the corner or 1933, they're all just directions to her. She goes where she likes."

"She's mad."

They'd reached the hospital steps. Johnny trudged up them.

She probably is mad, he thought. Or eccentric, anyway. I mean, if she went to a specialist and he showed her all those cards and ink blots she'd just nick them or something.

Yes. Eccentric. But she wouldn't do things like dropping bombs on Paradise Street. You have to be sane to think of things like that. She's totally round the bend. But perhaps she gets a better view from there.

It was quite a cheerful thought, in the circumstances.

Mrs Tachyon had gone. The ward sister seemed quite angry about it.

"Do you know anything about this?" she demanded.

"Us?" said Kirsty. "We've just come in. Know about what?"

Mrs Tachyon had gone to the lavatory. She'd locked herself in. And in the end They'd had to get someone to take the lock off, in case she'd fallen down in there.

She wasn't in there at all.

They were three floors up and the window was too small even for someone as skinny as Mrs Tachyon to climb through.

"Was there any toilet paper?" said Johnny.

The sister gave him a look of deep suspicion.

"The whole roll's gone," she said.

Johnny nodded. That sounded like Mrs Tachyon.

"And the headphones have vanished," said the sister. "Do you know about any of this? You've been visiting her."

"That's only been because It's, you know, like a project," said Kirsty, defensively.

There was the sound of sensible shoes behind them. They turned out to belong to Ms Partridge the social worker.

"I've phoned the police," she said.

"Why?" said Johnny.

"Well, she- oh, It's you. Well, she ... needs help. Not that they were any help. They said she always turns up."

Johnny sighed. Mrs Tachyon, he suspected, never needed help. If she wanted help she just took it. If she needed a hospital, she went where there was one. She could be anywhere now.

"Must have slipped out when no-one was looking," said Ms Partridge.

"She couldn't," said the sister stoutly. "We can see the door from here. We're very careful about that sort of thing."

"Then she must have vanished into thin air!" said Ms Partridge.

Kirsty sidled closer to Johnny while they argued and said, out of the corner of her mouth: "Where did you leave the trolley?"

"Behind our garage," said Johnny.

"D'you think she's taken it?"

"Yes," said Johnny happily.

Johnny was quiet on the bus home. They'd gone to the library and he'd wangled a photocopy of the local paper for the day after the raid.

There was a picture of people looking very cheerful in the ruins of Paradise Street. Of course, things were pretty faded now, but there was Mrs Density with her goldfish bowl, and Wobbler's grandfather with his bit of bomb and, just behind them, grinning and holding his thumb up, you could just make out Wobbler. It hadn't been a good photo to start with and it hadn't improved with age and he had soot all over his face but, if you knew it was Wobbler, you could see it was him all right.

They're all forgetting except me, he thought. I bet even if I showed them the paper They'd say, "Oh yes, that bloke looks like Wobbler, so what?"

Because ... they live here. They've always lived here. In a way.

When you travel in time it really happens, but It's like a little loop in a tape. You go round the loop and then carry on from where you were before. And everything that's changed turns out to be history.

"You've gone very quiet," said Kirsty.

"I was just thinking," said Johnny. "I was thinking that if I showed the others this piece from the paper They'd say, oh, yeah, that looks like ole Wobbler, so what?"