Knox laid Gaille down, brushed hair from her brow and cheek. The cut in her scalp was clotting, her complexion was perceptibly healthier, her breathing stronger. He stood up, took the torch from Lily, shone it around the new chamber, took it to the left-hand wall. It was coated with gypsum, and there were markings visible beneath the thick coats of dust. He took off his wet shirt, wiped it down, bringing a night-time scene to vivid life: people huddled in their beds as robbers roamed their houses, while outside lions prowled, snakes slithered, crocodiles lurked.
He went to the wall opposite, cleaned that too. A daytime scene. Akhenaten and Nefertiti handing out gold necklaces from a palace balcony while farmers went about their work, cattle grazed in the fields, ducks flew over the reeds and fish leapt in the lakes, all sporting in the beams of sunlight.
'It's The Hymn of the Aten,' he murmured. 'Akhenaten's poem to his sun god.' He illuminated the left-hand wall. 'That's the world by night,' he said. 'Lions coming forth from their dens, snakes preparing to strike.' He pointed right. 'And this is day. "Cattle and sheep welcome in the dawn, birds take wing as you appear. Boats sail upon the waters, all paths open through you."'
'What good is that?' said Lily, her voice cracking a little. 'We need to get out of here.'
The sunbeams converged towards the upper left-hand corner of the wall, Knox noticed. Yet they didn't meet. They hit the junction with the neighbouring wall before reaching their focal point, then promptly vanished. He turned the torch upon this wall, noticed something that had eluded him before. It wasn't a single flat surface, as he'd first thought. There was a recessed V-shaped section in its centre, set perhaps half an inch behind the rest, and it was actually at the base of this V that the golden thread stopped.
He placed his hand upon it, colder, smoother and altogether more metallic than he'd expected. He stepped back, illuminating the whole wall and the golden thread in the floor, and it reminded him of something. 'It's like a wadi,' he said, pointing out the valley-shaped V to her. 'You know, the one the sun rises over to make the sign of the Aten.'
'Then where's the sun?'
'Exactly,' nodded Knox. He went back to the wall, rapped his knuckles against it, listened carefully to the echo. He rapped again. Yes. No question about it. It was hollow.