‘They’re beautiful and they mean something.’ Leon continued. ‘They do. Goya was fascinated with satanism—’

‘Everyone was at that period in Spain. It was a fucking hobby,’ Ben replied drily. ‘There have always been theories about Goya’s work, but no one can prove any of them.’

‘What if I could?’ Leon challenged him. ‘In satanism, they decapitate their victims. When Goya died in France, no one gave a damn about his remains for over seventy years—’

‘Which is when the head could have been lost. Or separated from the skeleton when the body was moved.’

‘Goya’s head was stolen. Think about it, Ben. Perhaps the head could tell us something. An expert could discover if it had been cut off, or just taken after the body deteriorated.’

Staggered, Ben stared at his brother.

‘Even if it was cut off, that wouldn’t mean anything. Goya was an old man; it was a miracle he lived so long.’ He paused, staring at his brother questioningly. ‘What are you trying to prove? That he was murdered?’

‘He could have been! The Duchess of Alba was his mistress and she was poisoned. Goya had already suffered a very bizarre illness in his fifties and then he was sick again in his eighties.’

‘He was old!’

‘He was afraid.’

‘Of what?’

Leon glanced away. ‘There’s a coherent message in the Black Paintings – something Goya had to communicate. But he couldn’t put it in writing. That would have been too dangerous. He was afraid of Ferdinand, afraid that the Inquisition would come after him again. It’s no coincidence that when he finished the pictures, he went to France.’

‘And left a message behind?’

Nodding, Leon folded his arms, hugging himself. ‘Yes.’

‘For whom?’

‘I don’t know yet. For his peers. For his country. For posterity. I’ve not solved all the paintings but I’m close, really close. I don’t think Goya was mad. He may have wanted people to think that he was, but he knew what he was doing. He was a patriot. He’d seen his country gutted, he’d witnessed numerous atrocities. To see Ferdinand back on the throne after so much bloodshed, to see Spain under the royal boot of a vicious, conniving idiot would have been intolerable for him. And dangerous.’

Wary, Ben studied his brother: the flushed face, the clammy skin, the intensity which might precipitate an attack. If Leon did solve the mystery of the Black Paintings he would be thrust into the limelight overnight and come under attack, not least from his peers. He would be feted – and berated – for his theory, and bring a welter of jealousy down on his head. The Black Paintings were on a par with discovering the real sitter for the Mona Lisa: an intellectual prize that many had sought. Who in the art world hadn’t wanted to expose their meaning? It was a ticket to instant fame. And notoriety. But it was also an aesthetic cul de sac from which there would be no easy escape.

Leon’s expression hardened. ‘You think I’m getting too worked up about all of this.’

‘I think you might be tilting at windmills—’

‘Oh come on! What you really think is that I can’t deal with it.’

There was a long pause.

‘OK, you want me to be honest?’ Ben said at last. ‘Maybe I don’t think you can cope. Maybe I’m worried it will all get out of control—’

‘And maybe I don’t like being in control all the time!’ Leon retorted, flushed. ‘Maybe, being medicated to the bloody gills, I might miss the craziness. Did you ever think about that?’

Crazy was one thing, Ben thought, but the fall to earth which followed was always an unnerving affair.

‘Just take it easy, will you?’

‘Well, thanks for the advice, brother,’ Leon said, hurriedly getting out of the car and then bending down towards the window again. ‘Now, piss off.’

‘Before or after I’ve looked at the skull?’

Bordeaux, France, May 1828

Closing the door and locking it, the tall man lit another lamp, illuminating a laboratory of sorts. On the walls there were occult symbols, the pentacle and marked-out circles making swimming patterns in the half-light. Against one wall was a bench with a selection of medical tools laid on it, and beside that an oven. On top of the stove was a hotplate and a large stewing pan filled with water, a fire underneath. Rolling up the sleeves of his silk shirt, the tall man moved over to the sink.

The sack looked benign, with nothing to give away its ghastly contents, but he found himself momentarily unable to touch it. Pausing, he moved back to his desk and opened a ledger, making a few quick notes before returning to the sink. A moment passed and then finally the tall man opened the neck of the sack. The smell rose up and sickened him. Gagging, he put a cloth over his nose and mouth and reached into the bag. His fingers closed over a scruff of coarse hair. Then he gripped it firmly and withdrew the head.

The lamplight flickered, a vast, juddering shadow bouncing against the wall as the head became visible. Its sunken eyelids and rictus grin leered into the dim light as the man moved over to the stove and plunged the head into the warming water of the cooking pan. As he pushed it under, the skin of the face relaxed slightly, one eye opening, the cornea cloudy, staring up at him. Unnerved, the man slammed the lid down on the pan and moved away, rubbing his hands repeatedly to clean them.

At three o’clock in the morning, the clock chimed the hour sonorously. Now seated at his desk, the man waited. In front of him was a porcelain head, marked out in portions to indicate the parts of the brain which controlled the mind’s workings: intuition, intellect, emotion. A book next to it was marked Phrenology, the new popular science by which men of reason believed they could read the character and ability of a person merely by studying the bumps and indentations on their head. It had become a cult all over Europe, a pseudo-medical curiosity, every adept eager to ‘read’ the skull of a genius to see if there was anything truly remarkable about its configuration.

Behind him, the man could hear the water simmer, the smell repellent as he lifted the lid off the large pan. Flinching, he could see that the skin was coming away from the bones of the skull, a sudden hissing noise startling him as one of the dead man’s eyes popped out of its socket. Fighting nausea, the man pushed the head further down into the boiling water, the dark hair – ribboned with grey – floating upwards, loose flesh pooling greasily on the surface.

Slowly the night wore on, the man not daring to leave his watch. Outside, the darkness remained thick, the clock markingout the leaden heartbeat of the house. Exhausted, he fell into a nervous sleep: the cold, queasy sleep of the early hours. The temperature in the room dropped, the night owl stopped hooting, and the only sound came from the hum of the fire and the foul, simmering water.

Half an hour later the man woke, alarmed, sitting upright and then remembering where he was. Uneasy, he rubbed his eyes – and then stiffened in his seat. From behind came the sound of knocking. A steady, rhythmic knocking which was very close. Terrified, his limbs frozen, he slowly turned his head a little to the right. The sound intensified … Was someone knocking on the door? Did someone know he was there? Had the grave robbers betrayed him? The lamps had all but gone out, the shadows cloying as the man finally staggered to his feet. Moving to the door, he stopped abruptly. The noise was coming from the pan.

His gaze fixed on the gleaming copper tomb as he heard the steady, rhythmic knocking and watched in horror as the fire suddenly flared up in the stove and the water hissed and bubbled. It boiled so urgently that the knocking speeded up even more: increasing, manic, deafening. Transfixed with shock, the man realised that the noise was the head banging against the lid. Knocking on the lid, trying to get out … Then with one sudden burst of energy, the white-hot water tossed the lid aside, toppling it on to the floor, the skull bobbing to the surface of the searing, stinking liquid.