Tiaan had been carrying the dead child for the best part of a day before she realised that something was following her. She was being hunted through an abandoned city.

She scanned her surroundings, but nothing moved in that vast chamber. An oval ceiling, carved from the solid heart of Mount Tirthrax, arched high above. Caverns ran off in five directions, though none were lit. She was somewhere inside Tirthrax, the Aachim’s most magnificent city, though she had no idea where.

Her life lay in ruins. Tiaan had trekked halfway across Lauralin to save Minis, her lover-to-be, but he had cast her aside. The Aachim people had callously taken advantage of her soft heart, but in saving them she had betrayed her world. And little orphan Haani, her adopted sister, was dead – killed by an Aachim javelard in a terrible, senseless accident.

Laying Haani on the dusty floor, Tiaan sat beside her, but felt so weak she had to lie down. Her whole body was trembling. In the distance, a walkway of wires and crystal spiralled through floor and roof. She had climbed several like it in her dismal trudge through the empty city. Each time she encountered a stair, Tiaan had gone up. There was no reason for it; her feet had just taken her that way.

Haani’s cheek was waxy pale; her striking, lime-green hair had gone limp. The clothes she had dressed in so carefully were filthy. Feeling a tear welling in one eye, Tiaan ground it away with her fist. If she allowed that, she might never stop.

First she would find a suitable place to lay the child to rest. Somewhere pleasant, by a window, if there was one in this accursed city. Then she would lie beside Haani and they would sleep together, forever.

A noise roused Tiaan; a footstep on one of the crystal treads of the stair. Had the invading Aachim come back to finish her and seize the amplimet, the magical crystal that had allowed her to open a gate from here to Aachan? Let them have it. She never wanted to see it again. Though Tiaan had left the amplimet behind, she felt no withdrawal. She had felt nothing since the gate had opened.

Tiptoeing across to the hole through which the stair passed, she peered over the rim. Far below, she saw the top of a man’s head. Further down on the looping staircase, no more than crystalline treads strung on taut wires, crouched a woman with a black band over her eyes. She had a small, pale face and hair like colourless silk. Her arms were wrapped around the side wires of the stair.

The man went down to her. It was Nish from the manufactory! Cryl-Nish Hlar, her enemy. Tiaan had once rejected his advances and he had never forgiven her. He must know about the gate and the Aachim. If he caught her, it would mean a death sentence.

Tiaan pulled back from the edge, out of sight. How had he found her here, hundreds of leagues from the manufactory? It did not seem possible, yet here he was. The manufactory must be determined to get her back.

Haani’s body lay like a rag on the dusty floor, as cold as the glacier that had broken through the side of the mountain when the gate opened. Her hair was now covered in feathery frost. Tiaan picked the child up and for the first time felt her weight. She was so tired.

She looked around despairingly. Far off to her right Tiaan spied another stair, this one a ribbon of metal swirling up to what, in the dimness,