Ben had been repelled, but compelled to look at the painting: at the stupid, animalistic faces of the cohorts crouched on the ground. Women, once beautiful, had been turned by Goya into salacious hags, monochromic heads cowled, eyes wide open and blank with cruelty. And while Detita talked of Goya, she also talked of Spanish history – and the unknown. Of the two boys, she had caught Leon’s imagination first because he was mercurial in temperament, needing constant excitement and stimulus.

Ben was never sure if their parents had understood Leon’s mental frailty, but he had been aware of it all his life – that nauseous dance between stability and hysteria, between appreciation and obsession.

Still staring out of the car window, Ben remembered Detita. The Detita of the daytime, practical, intelligent, stern. And then the other Detita, the night woman, languid as candlelight. Duty had had no place after the light faded – then she had told stories, stories she said had been passed down by generations of Spanish grandmothers, by her Spanish grandmother. But the tales had never been benign. Always, like her, they veered between two worlds.

‘… When you need me, come at midnight to the Bridge of the Manzanares, clap your hands three times and you will see black horses appear …’

Detita had smiled as she recited the quote, Leon leaning forward expectantly under the overhead lamp, Ben’s dark eyes fixed on her. At once she had noticed his expression, the almost warning glance, and felt her power weaken. Many times in the years that followed she had clashed with Ben as her control over him lessened. And then, finally, Detita had shifted her attention from the two brothers to the one. From Ben’s granite control to the soft slush of Leon’s instability.

For an instant, Ben closed his eyes. But still the memories kept coming.

‘… The Spanish people have a dark heart …’ Detita had said, luring Leon in with her stories. ‘When Ferdinand VII reinstated the Inquisition the purges began, the Church re-energised along with its greedy, mercenary priests. And among the pogroms, the Spanish developed an even greater appetite for pain, murder and death. Goya feared Ferdinand because he was a liberal, and after Ferdinand was reinstated the King’s power was absolute again.’

A fly landed on the back of Ben’s hand, throwing a stumpy shadow before he flicked it away. In the overheated car, he wondered why Leon wasn’t talking and glanced over at his brother. Was Leon waiting? Was he biding his time? Or maybe just sulking? Suddenly another memory resonated in Ben’s mind: his brother waking, screaming, in the middle of the night. Every night throughout one long, dry summer as Goya’s image of Saturn picked away at his sanity like a black rook. Relentlessly, Leon had insisted that the house was haunted, that their dead parents lived in the cellar and banged on the water pipes …

Pleading, Ben had asked Detita not to tell Leon any more stories. She had replied with a limp shrug, smile benign as a lamb’s, eyes like a tree monkey.

‘They’re just old Spanish tales!’ she had said. ‘Children have to know about the world, not just the part they can see. Leon might be scared for a while, but then he’ll forget. No one stays frightened forever.’ She had been playing cat’s cradle with Ben’s emotions, unexpectedly tender. ‘You’re a good boy to worry about your brother. You must always look out for Leon – he’s not strong like you.’

‘So?’

Startled out of the memory, Ben turned to his brother. ‘What?’

‘So will you help me?’ Leon went on, his skin translucent, pale after a lifetime of ducking the Spanish sun. ‘Will you get someone to look at the skull?’

‘Yeah, OK,’ Ben said finally.

‘Thanks …’ There was an awkward pause. ‘You’re staying overnight, of course?’

‘I’ve got a hotel room booked in Madrid.’

‘Madrid? Why don’t you stay with us?’

‘I’ve an early flight in the morning. Why disturb everyone?’

‘But I want you to meet Gina,’ Leon replied petulantly. ‘I want you two to be friends. I was never lucky with women before, you know that. But Gina’s perfect. She understands me, my work. I want you two to get on.’

‘I’m coming back next month. I can meet her then.’

‘Why not now?’

‘Leon, next time, I promise.’

‘She’s very supportive—’

‘Good.’

‘Really cares about me.’

‘That’s good.’

‘Very understanding—’

‘She broke up with you for nine months and then came back without ever explaining why she went off in the first place!’

Ben stopped short, cursing himself. Leon’s tone was prickly as he replied.

‘Gina left because we had problems. It wasn’t all her fault. We’ve sorted things out now … She’s good for me, Ben. She’s interested in sport, health. She said I didn’t need to take so much medication—’

His patience strained, Ben stole a quick glance at his brother. ‘You need it, Leon—’

‘Yeah, I do now, but in time Gina says I won’t. She knows all these people who practise alternative therapies; they’ve had great results.’

‘Perhaps you should talk your doctor about it.’

He was sharp. ‘I’m not a child!’

‘I’m not saying that, Leon. I’m saying that it would be a good idea. You could take Gina with you.’ Sighing, Ben tried to break the tension by changing the subject. ‘I’ll pick up the skull on my next trip—’

‘Why can’t you look at it before you leave?’

‘You’ve got it?’ Ben asked, surprised.

‘Of course.’

‘Shouldn’t you tell the authorities?’

‘I have done. And I told the Prado that I’d organise its authentication for them. I’m well respected here, they trust me to do the right thing.’ Leon’s voice held a slight tremor of triumph. ‘Gina said I should do what I’ve always wanted to do – to finally write that book about Goya’s Black Paintings. God knows I’ve done enough work on them. I’ve the chance to solve the pictures. Just think of it – a book to coincide with the exhibition and the finding of the skull.’

‘But you don’t know if it’s authentic—’

‘You don’t know it isn’t!’ Leon’s pale eyes were fixed on his brother. ‘It’ll be the making of me, Ben. I’ll be the only historian who can lecture on Goya and exhibit his skull at the same time. Think of it – people love the macabre.’

‘Leon, about the Black Paintings …’ Ben began anxiously. Memories of Detita, of his brother’s instability, shivered inside him. ‘I’ll get the skull checked out for you, see if it’s authentic. I know someone in London who can do that for us. But I don’t want you to do the book.’

‘Why not? I’ve been talking about it for years,’ Leon replied, bemused. ‘Why would you want me to pass up on it now?’

‘Detita used to say that the Black Paintings were cursed. She said they were bad luck—’

‘Since when did you believe in things like that?’

Ben sighed. ‘All right, but I don’t think it would be good for you.’

‘I know more about the Black Paintings than anyone. Anyway, I’ve got a new theory—’

‘No one really knows what they mean,’ Ben went on. ‘They don’t make sense.’

‘They do!’

‘All right, maybe they do. Or maybe they’re simply gibberish. I don’t know if Goya was ill when he painted them, or smoking something. But I know those pictures, Leon, and they’re disturbing. Detita was right about that. They’ve caused so much speculation: crap about codes, hidden messages, even—’

‘A link to the occult.’

‘Which is unproven,’ Ben said emphatically.

‘But suspected by a number of people. After all, Goya didn’t just paint one or two satanic paintings, he undertook dozens. He was consumed with the dark side—’

‘And you? Are you consumed? Because if you are, that worries me.’

Leon blinked slowly, his tone sarcastic. ‘Paintings aren’t dangerous. They can’t harm people …’

Incredulous, Ben shook his head. Of all the people in the world his brother was the most likely to be harmed by the queasy allure of Goya’s last works.