‘Debts can be rearranged,’ I said easily. Perhaps too easily. He spun around and fixed me with a hard look.

‘The book will be finished on time. We must redouble our efforts. Perhaps some aspects of the process can be rethought.’

‘What aspects?’

‘The rubrication, for one. I have been in the press room – I have seen how much time we lose inking the form in two different colours. Sometimes I have seen black ink spill over into the red, and then the whole form must be removed, wiped off and inked again.’

‘It is time-consuming,’ I admitted. ‘But we will not be able to charge so much if we sell the books without rubrication.’ In truth, I hated the thought of another man’s hand in my book, marring the unity of the whole.

‘Nonsense. The customers will not know what they are missing. Any one who buys a Bible expects he will have to pay a rubricator, just as he expects to pay the binder and the illuminator.’

‘Not the illuminator. They will have Kaspar’s plates.’

We stopped by the embankment. The river lapped against the wall below; a flock of swans pecked at the weed that trailed from the stones.

‘Those must go too.’

Without looking, Fust must have known the expression on my face.

‘I know he is your dear friend. But we have invested too much in this to allow mere friendship to threaten it.’

Mere friendship. ‘He is more than my friend. He was the root and stem of all that we have done. He had already pressed his cards while I was still copying schoolbooks in Paris.’

‘Then he will understand that a new art requires compromises.’

I doubted that very much.

‘Is there anything else?’ I asked.

‘You should look at the composition of the pages. Peter thinks that you could fit two more lines on every page without changing its appearance. More lines on the page means fewer pages in the book. Less paper and time, more money. That alone would account for almost half the time we spend pressing the extra copies.’

‘I will consider it,’ I said stiffly. For all my age, I felt like a child denied the toy he was promised. I wanted to weep.

Fust slipped a rosary from his wrist. He flipped the beads around in short, precise movements, like counters on an abacus.

‘You cannot do everything, Johann. This book is already a miracle. In two years we will produce more books than one man could in two lifetimes. We must not overreach ourselves.’

‘This was my dream,’ I whispered. ‘God’s word as God intended it.’

‘The words do not change. It is only the ornament. For God’s sake let it go. We have invested too much to fail because of it.’

‘I am not doing this for profit.’

‘No? I saw your face when I told you how much we will earn from the extra copies. But even if you are not – I am. And you are working for me.’

‘A partnership.’

‘If you do not like the terms I am happy to dissolve it.’ He slapped the rosary into his palm and closed his fist around it. ‘I did not mean that. I know how much this means to you. But you, of all men, must be practical.’

He watched me for a moment, then rattled the rosary back over his wrist. He sighed, made to leave, then remembered something.

‘I made an inventory of our vellum stocks yesterday. Three skins were missing.’ He peered at me closely. ‘I heard that you pressed a batch of grammar books in the Gutenberghof last week.’

‘The parchment we were going to use got wet. It would have crumbled like pastry when it dried. I had promised the books would be delivered on time, so I borrowed some from the store at the Humbrechthof. I will replace it as soon as I get a new batch.’

His eyes blazed. ‘Do you remember what I told you? Everything that goes into our venture stays in it. You cannot borrow, like a labourer in the vineyard stuffing his face with his master’s grapes. I will allow it this time, but never let it happen again.’

He left me on the quayside. Out in the stream, the wheels on the mill ships turned on. It suddenly occurred to me that my mother must have stood here, decades earlier, watching her youngest son embark on a barge to Cologne with little more than a clean shirt to his name. Did she weep? Did she feel her life torn away from her: first her husband, then her child? Did she think on what might have been?

Fresh raindrops dashed against my face, mingling with the tears.

LXXIII

River Rhine

Nick stood in the bow of the boat. Spray spattered his cheeks, but he would rather endure that than the suffocating, tobacco-laden fug inside. He felt as if he was sailing into a fairy tale. Not the modern sort, with wisecracking animals and songs written to sound good as ringtones; the old-fashioned kind, tangled tales woven out of the fabric of the land, dark forests and hard mountains. Here, the Rhine flowed through steep-sided valleys covered in snow, under great cliffs where sirens once lured sailors to their doom. Stark castles guarded every hilltop, watching the boat as it crept downriver. Some were tumble-down ruins; others looked as though they only wanted a trumpet call to rouse their defenders to battle.

‘It’s just as well we came by boat.’ Emily pointed a gloved hand to the shore. A single road wound along the riverbank, tucked into the slope. It was almost invisible under the snow. ‘No cars. They must have shut it.’

‘Good,’ said Nick. ‘Harder for anyone to follow us. Unless there’s another ferry?’

‘The bartender said this is the last boat today. He said there might not be any tomorrow either if the ice gets worse.’

‘Good.’ Nick repeated it, trying to convince himself. He was afraid. Not the sudden pulse of adrenalin that came with being chased – he’d had plenty of that in the last ten days. This was a deeper dread, cold fingers slowly choking him as he sank into a void. A feeling that there was no way back.

Emily pulled out a rumpled paper tissue and began shredding it between gloved fingers, letting the fragments fall into the water. ‘Do you think we’ll find it?’

‘Do you mean her?’

‘Sorry.’ She watched a piece of tissue flutter down. The river soaked it up.

Nick didn’t speak, but shuffled sideways so that he squeezed against her. She tipped her head so that it rested on his shoulder.

‘I wonder how the prayer of Manasses fits into this,’ she said.

‘What do you mean?’

‘We’re following Gillian. But what was she following? If she went to Oberwinter, it was because of what she found in the Mainz archives. Nothing to do with the prayer of Manasses or the digging bear.’

‘Maybe we were on the wrong track with the pictures,’ said Nick. ‘The Sayings of the Kings of Israel is supposed to be a lost book of the Bible, right? Maybe that was the writer’s way of saying that his book’s gone to this place where lost books go. The Devils’ Library.’

‘But the bear. Do you think it’s a coincidence that the picture from the card was right there in the prayer of Manasses?’

Bear is the key.

‘You said yourself that medieval artists copied each other all the time.’

‘It feels as if we’re following a trail that someone laid down for us five hundred years ago. The hard-point inscriptions, the hidden books, the recurring images… But I’m not sure it points to Oberwinter.’

‘Gillian was.’

Nick pulled away slightly, but only so he could stick his hand in his pocket to warm it. His fingers touched the slim bar of his cellphone, tingling as the blood returned.

No. It wasn’t his blood, he realised, but the phone vibrating. It was ringing as well, though with the engines throbbing through the boat and the hiss of the water he hadn’t heard it. He must have forgotten to turn it off when he’d used it to read the hard point.

He pulled it out, staring at it like a relic of some alien civilisation. And then, because he was tired and it was a ringing telephone, he answered.