‘Where?’

‘The back door? Come on!’

‘We haven’t done anything wrong!’

‘How do you know?’

Kasandra opened the back door and hurried down the path and into the garage, dragging Johnny behind her. The trolley was still in the middle of the floor.

‘Get ready to open the big doors and don’t stop for anything!’

‘Why?’

‘Open the doors now!’

Johnny opened them, because practically anything was better than arguing with Kirsty.

The little garage area was empty, except for someone washing their car.

Johnny was nearly knocked aside as the trolley rattled out, with Kasandra pushing determinedly on the handle. It rattled across the concrete and lurched uncertainly into the alleyway that led to the next road.

‘Didn’t you see that programme about the flying saucer that crashed and these mysterious men turned up and hushed it all up?’ said Kasandra.

‘No!’

‘Well, did you even hear about the flying saucer crashing?’

‘No!’

‘See?’

‘All right, but in that case how come there was a TV programme about it, then?’

A car edged around the corner into the road.

‘I can’t waste time answering silly questions,’ said Kasandra. ‘Come on.’

She shoved the trolley as hard as she could. It rolled down the sloping pavement, the squeaky wheel bouncing and juddering over the slabs.

The car turned the corner very slowly, as though driven by someone who didn’t know the area very well.

Johnny caught up with Kir-Kasandra and clung to the handle because the trolley was rocking all over the pavement.

The trolley, under its heavy load, began to pick up speed.

‘Try to hold it back!’

‘I’m trying! Are you?’

Johnny risked a look behind. The car seemed to be catching up.

He jumped onto the trolley.

‘What are you playing at?’ said Kirsty, who was far too worried to remember any new names now.

‘Come on!’

He grabbed her hand and pulled her up on the other side of the cart. Now she was no longer holding the handle, it surged forward.

‘Do you think this is really a time machine?’ he said, as the rushing wind made the bags flutter.

‘It must be!’

‘D’you see that film where the car travelled in time when it went at eighty-eight miles an hour?’

They looked down. The wheels were screaming. Smoke was coming out of the axles. They looked up the hill. The car was catching them up. They looked down the hill. There were the traffic lights. The Blackbury by-pass was a solid wall of thundering traffic.

Then they looked up into each other’s frightened faces.

‘The lights are red! The lights are red! I don’t want to die!’ said Kirsty. ‘I haven’t even been to university!’

One hundred metres ahead, sixteen-wheeled lorries barrelled onwards, taking a million English razor blades from Sheffield to Italy and, coming the other way, a million Italian razor blades from Rome to England.

The trolley was, without a shadow of a doubt, going to smash right into the middle of them.