The voice said: “The thought mirror was perfected by an ancient civilisation called the Aztecs; their shamans used it in meditation before performing a human sacrifice. The secret was rediscovered by paranormal researchers in the late twentieth century. It has the power to coordinate mental vibrations from the brain, the heart and the solar plexus. Now try to memorise the map.”
Niall stared intently at the map. To his surprise, it no longer cost him a mental effort to grasp it as a whole. It was as if his powers of concentration were somehow aided and amplified by the mirror hanging on his chest. Five minutes earlier, the map had seemed too complicated and undigestible; now, suddenly, it was as if his mind was absorbing it hungrily, as his stomach might absorb food. In less than a minute, he knew it by heart.
He asked: “What is the Fortress?”
“It used to be the main barracks of this city. A barracks is a building that houses soldiers.”
“And what is an arsenal?”
“A place where weapons are kept.”
He pointed to the map. “Is the bridge guarded?”
“Yes. Last week, one of the commanders was caught as she tried to wade across — she wanted to get to the nursery to see her baby. Now wolf spiders guard both ends.”
“What happened to her?”
“She was publicly executed and eaten.”
“Is there any other point where it is possible to cross the river?”
“The bridge is still the best. The river is at its shallowest there.”
“When would be the best time to attempt it?”
“At dawn, when the guard is changed.”
Niall studied the map again. It would obviously be suicidal to try and approach the bridge down the main avenue. But the map showed flights of steps descending to the river at intervals of about half a mile along its embankment. If Niall could gain access to the river near the wall that divided the city, it should be possible to make his way to the bridge along the lower bank.
“Where should I look for shelter in the slave quarter?” he asked.
“Many of the buildings have lost their upper storeys. The spiders prefer not to use these for web-building. You would be safest in one of those.”
Niall experienced a twinge of pain behind the eyes; when he massaged his cheeks and forehead with his hands, it went away.
The voice said: “The pain is due to the thought mirror. You are not accustomed to using it, and unless you keep your attention concentrated, it will cause headaches. When that happens, turn it round the other way.”
Niall turned the mirror so that it faced away from his chest. As soon as he did this, the sense of strain vanished. But he observed that he now felt curiously fatigued. The blood tingled in his cheeks. He lay down on the couch and closed his eyes. A pleasant drowsiness began to steal over him.
The voice said: “It would not be advisable to sleep now. The Spider Lord has just sent a message to Kazak, asking him to bring you to his presence. When Kazak admits you have gone, every spider in the city will be searching for you.”
Niall sat up, his fatigue vanishing instantly. Once again, he had to control the fear that trickled into his bloodstream. He had to keep his voice steady as he asked:
“What will he do to Kazak?”
“Nothing. The Spider Lord is a realist. But you must leave now.”
“Yes.” An effort of concentration subdued his fear and renewed his determination. “Shall I be able to keep in touch with you?”
“Yes. Through the telescopic rod. It is attuned to the thought pattern of the Steegmaster. But use it sparingly. Many of the spiders will be able to detect its energies. So whenever you use it, you will be in danger of discovery.”
The old man suddenly appeared, standing by the white column. “Before you leave, I would advise you to eat. You have a long night before you.”
“I don’t feel like eating.” His appetite had vanished.
“Then take food with you. You must also change into the uniform of the slaves. Follow me. There is now no time to lose.”
Niall stepped into the column and felt himself descending; this time the feather-like sensation was unpleasant, underlining his nervous tension.
They were in the room with the white curved walls. On one of the stools — the one that Niall had mistaken for a weed-covered rock on the seashore — lay the telescopic rod and the coarse grey uniform of a slave. As he slipped it on over his own clothes, his nose wrinkled in disgust; it smelt of stale sweat.
Unlike his own garments, the slave uniform had two wide pockets. There was something in both of them. He investigated and found that one contained a small wooden box. In the other was a light grey tube, about six inches long and an inch in diameter. In the box, under a layer of cotton wool, were a number of tiny brown tablets. The old man said:
“These are food tablets — a type developed by men to sustain them on long journeys in space.”
“And this?”
“A lightweight garment, also developed for use in space. Touch the disc at the end.”
When Niall pressed the end of the tube with his thumb, it elongated to twice its length, then unrolled. It was a baggy garment of dull metallic grey, and looked big enough for a man twice Niall’s size. He asked:
“Is this necessary?”
Take it. You may be grateful for it. When you press the end it will re-fold itself.” Niall watched with amusement as it converted itself into a neat grey tube, and was surprised that it did this so silently without any of the rustling noise he would have expected.
“Now go, otherwise all the preparation will have been wasted.”
He vanished. Niall felt disconcerted by the abruptness of the leavetaking, but it emphasised the sense of urgency.
As soon as he picked up the metal rod, he experienced a tingling sensation in his fingers; when he reached out and touched the wall with its end, his legs felt weak and he was overcome by sudden dizziness. He stepped forward and felt again as if he had fallen into a whirlpool. For a moment there was acute nausea; then his senses cleared and he was standing on the grass outside the tower.