‘They’re amazing. They’ve served you for too long. They deserve to be free. You owe it to them!’

Jack folded his hands together, infuriatingly calm. ‘Well, Thomas Swinton, you do surprise me.’

‘Tommy, please, don’t!’ Zita’s voice came from her prison, far off and strange.

Tom took one last look at Zita. She was pressed as closely as she could be against her side of the glass. He reached out and touched his fingers to her forehead, and she bowed, as if feeling the pressure. He was sure in that moment that he loved her. Sure that he had always loved her, maybe even from the moment that she had first appeared to him at school, carrying the letter.

Then Tom turned his back on her, ignoring her pleas.

‘I want proof. I want proof that you’ll set them free. That you’ll release them. Both of them.’

‘Good man. You are a Swinton after all. Well, then, you have my word as a Swinton. That is all that has ever been needed.’

‘And you have mine.’

Jack reached his gnarled hand out, and Tom slowly moved towards it.

They shook hands.

Tom felt the harsh electric surge of possibility in the old man’s fingers. He fought the fear in his stomach, the grim taste in his mouth. The next words he spoke were quiet but clear.

‘Now. Show me.’

Jack nodded, and a glimmer of something that Tom had not seen before passed behind his eyes, like grudging respect. He glanced behind and saw that Zita had retreated, her face in her hands.

She would be free. So why was she unhappy?

Tom shuffled round to the other side of the desk, and Jack took his time finding the key, opening the drawer and taking out the iron-bound box, as if it were a rare and precious jewel.

He could not hide the look of triumph on his face.

‘Put your hand on mine.’ He was gloating.

Tom, resolve forming in his mind, did so. The old man’s skin was rough, and Tom considered that he was holding the hand of a man who had been born in the sixteenth century.

How must he have felt, to witness the coming of electricity and motors and oil and engines? Had Jack watched in wonder when he saw the first aeroplane tearing through the clouds?

Looking at Jack, Tom sensed that he was dead inside, and that he had been dead for as long as he was able to remember. Only the past was alive for him.

Tom did not want to be like that.

And yet he had chosen.

Once more, the world changed. The dizzying sensation, the sickness, the pull in his stomach, the blackness, the elation.