Clean air came from above, and the torch flame flared brightly. Tisamenos felt a cool breeze on his face as his father moved around. At every few steps he paused and lit a torch. Soon there were a dozen or more, all blazing.

Tisamenos could now see clearly the huge black stone structure that occupied the centre. It was carved with all sorts of pictures which, as he drew nearer, he saw were human figures.

‘Here they all are,’ said Orestes, gruffly.

‘All who?’ said Tisamenos. Orestes drew closer and traced his hand over the image, as if he were caressing it.

‘All of them. All of us. There.’ He grabbed his son’s wrist, and pulled him to the right-hand side of the cube. ‘Tantalos, your ancestor, who out of arrogance served his own son to the gods.’

‘That’s just a story. Isn’t it?’ Tisamenos said, nervously.

Orestes laughed, and Tisamenos could smell the wine on his breath. ‘Depends on what you mean by just a story.’ Tisamenos gulped. ‘There is a lot of truth in stories. And here, look, is Atreos, who killed his own brother’s children – apart from one, of course. Bit closer to home, that one, isn’t it?’ Aegisthos had been the one that survived. Aegisthos, Erigone’s father. Could Orestes know about Erigone too? Had Electra told him? If he did know, why wasn’t he taking his own revenge? Why was his father bringing him down here, into the dark, away from the light? He felt suddenly afraid.

‘Father – what do you want me to do?’

‘To see, of course. To understand.’ He pressed the face of Tantalos, and a small opening appeared in the surface of the cube. Stretching down into the darkness was a flight of stairs.

‘Here. Now. Come and see.’ Orestes went first. All trace of the uncertainty had left his steps, and Tisamenos was beginning to see something of what Orestes had been like as a young man returning from his forced exile to reclaim his kingdom from his own mother and her lover. Orestes was going briskly down, and Tisamenos wondered how often his father came here.

A scratching noise, like that of claws on stone, unnerved him. It was much colder now, and there were goosebumps on his arms. The noise was outside of him. Was it some kind of beast? The scratching sound became a scrabbling, as if whatever it was that was down there had sensed they were coming.

Halting at the bottom of the stairs, Orestes spoke. In the light of the torch he looked bold and powerful.

‘Don’t go near her,’ he commanded.

They were now deep underground. How large the chamber was Tisamenos couldn’t tell. In front of him, larger than a grown man, manacled by a long, thick iron chain, was a dark, hunched-up creature.