But today Acir kept the musicians in sight; today he saw them turn aside from the busy market thoroughfare and – disappear.

Acir followed, hastening his pace. Steep steps, with only an iron handrail to cling to, plunged down the hillside between ramshackle terraces. There were many of these precipitate stairways in Sulien, winding down beneath ancient arches into squalid courtyards or weed-grown lanes, behind the ornate façades of the crescents and squares.

This stair led nowhere. A blind alleyway, the sheer walls on either side windowless, blackened with soot, damp and clinging moss.

Acir turned around. There was no other way out. The Magelonne girl had tricked him again.

Then he saw it. At the far end of the alley, an archway, overhung with dark, dusty ivy, concealed an iron grille. A carved stone face stared out from between its leafy crown of glossy green, its sunken eye sockets empty, seeing nothing: a sightless mask of death. The grille beneath led down into darkness. Into the Undercity.

Acir came closer. He had no lantern to light his way below ground. But he was certain he was still on Khassian’s trail. This was not the moment to turn back for want of a torch. He slipped beneath the trailing curtain of ivy and tested the handle of the grille. The rusted iron hinges groaned – then, as he exerted greater pressure, slowly opened. Far ahead in the darkness he caught the dwindling flicker of lanterns.

Darkness, secrecy, concealment – the whole escapade stank of conspiracy.

He sighed. He had no choice now; he must follow them into the dark. And the lights were so far ahead, he would soon lose them altogether.

He pulled the grille to behind him and set out warily in the darkness. He had not forgotten the vast reservoirs that lay below ground… or the vicious water-snakes that lived in their murky depths.

The flickering lights went on some way ahead of him. This was too easy. Had the composer become careless? Or did he just not care any longer?

The lights suddenly vanished.

Acir stood alone, lost in the utter blackness, listening in vain for a footfall, a dislodged stone, even the distant drip of water.

Should he feel his way back to the entrance, hand over hand? And which way was the entrance? Was the only alternative now to go on into the dark?

Slowly, uncertainly, he went blindly forward, still listening attentively.

He had expected to hear the murmur of voices, hushed, conspiratorial. But all he could hear was – singing.

They were musicians, after all. And musicians needed to practise their craft.

He crept closer, drawn towards the faint strains of music until he reached a tall doorway cut into the rock.

Voice intertwined with voice, clashing then resolving into a melting sweetness.