'What's the matter with your machine?' said Tiaan, ignoring the question.

'The node has gone dead and taken all the fields with it.' Tirior was watching Tiaan, head tipped to one side, no doubt wondering how the walker could still move. It would not take her long to work it out.

'Merryl' Tiaan said quietly. 'Order your people to take the Aachim, before they attack us.'

Tirior's hand darted for the pack she wore on her chest. Tiaan hurled the walker backwards, slamming painfully into the wall.

'Take them,' roared Merryl, throwing his handless arm across Tirior's throat and twisting her other arm up behind her back. The freed slaves did the same with Minis.

'Him as well' Tiaan shouted, pointing to Nish.

'You misjudge us' Tirior said softly, but under her breath she was muttering in an Aachim dialect Tiaan did not recognise.

Tiaan felt power flow from her controller and the walker's legs slowly splayed. Had Tirior not been exhausted from the mancery that had got her into Snizort, she might have succeeded.

'Stop her mouth!' Tiaan cried.

One of the slaves wound a strip of cloth three times around Tirior's head and pulled it tight. Tiaan felt the flow ease. Her heart was beating irregularly and she felt faint. So close.

'You taught me the value of your word, Tirior.' Tiaan wrenched open the pack, Tirior had been reaching for a small glass tube, capped in gold, with a scintillating powder inside. Tiaan tossed it into the tar and pressed it down with one of the walker's feet. 'Bind them, please. Merryl.'

Cord was found in a storeroom and the three prisoners' hands bound behind their backs.

'I'm not your enemy, Tiaan,' said Nish. I was wrong about you before. I'm sorry.'

He seemed different to the Nish Tiaan had known. He was more sure of himself, less angry, and made no attempt to fight those who held him. But Tiaan could not forgive so easily. 'Every time I've met you I've regretted it, Nish,' she said wearily.