Now his younger self strode forwards over the field towards the woods. Kit appeared to be dragged behind him. Tom knew where they were going.

Things around them began to shake and shiver, and then they were back in Jack’s rooms. Tom wondered if it was getting harder and harder for Jack to go back, for the old man seemed briefly a frail shadow of himself, resting his head on the desk.

Once more Tom felt bereft. The sound of a plane in the sky above the house made him clutch his head. It was too loud, too strange. He began to see why Kit hated mobile phones so much; why he had shrunk from the bus, and the smell of oil. All the noise, all the bustle of the twenty-first century seemed so clangorous and empty.

After a minute or two he looked up, to see Jack, haggard and ancient, with a small smile on his face.

‘Is there anything you wish? Anything in all of time.’ Tom nodded slowly and sat up.

‘Show me.’

Tom took the photograph of his father and mother out of his pocket and placed it on the table.

Jack sighed. ‘Your father. I had no need of him. He had no gift. Perhaps I should have tried to know him. You want to see them. Your mother.’

‘You could have saved them? Could you save them?’

‘I could have changed nothing. I can change nothing. But if you want to see them …’ Jack stood up, and paced towards the window, where once more he stood in the dappled light, looking out across the lawn towards the woods. ‘There is a price.’

Tom shivered. He felt a great desire to touch the jewelled box. Jack would be able to show him his parents – and everything else. The whole universe opened up in front of him.

‘What else can I see?’

Then Jack turned round with a terrible grin on his face. ‘I can show you everything. I can show you the birth of our Saviour Lord Jesus Christ, when the world shook. I can show you his death, when the world wept. I can show you Good Queen Bess riding a white palfrey through the woods to meet her lover. I can show you the antique emperors, and Julius Caesar murdered in the Senate. I can show you the stones of Stonehenge raised up. I can show you all that is past, anywhere in the world.’

‘Anywhere?’

Jack snorted. ‘Anywhere – and beyond. The things the Samdhya know are things that no man has known, nor ever will …’ His eyes shone, and Tom saw in them a much younger man, a man full of a thirst for knowledge. ‘There are spheres of light and power and radiance.’ He paused. ‘Angelic, crystalline, divine.’

The possibilities were dizzying. ‘And … the future?’