‘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.’

Yo-less 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 Yo-less. ‘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 smashed-up 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 Yo-less.

‘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.