In the early pre-dawn hours of the day assigned to Siona Leto descended to the crypt and gave orders to his guard that he was not to be disturbed by anyone. His cart sped him down one of the crypt’s dark spokes where he opened a hidden portal, emerging in less than an hour at the Little Citadel.

One of his delights was to go out alone on to the sand. No cart. Only his pre-worm body to carry him. The sand felt luxuriously sensuous against him. The heat of his passage through the dunes in the day’s first light sent up a wake of steam which required him to keep moving. He brought himself to a stop only when he found a relatively dry pocket about five kilometres out. He lay there at the centre of an uncomfortable dampness from the trace dew, his body just outside the long shadow of the tower which stretched eastward across the dunes.

From a distance, the three thousand metres of the tower could be seen as an impossible needle stabbing the sky. Only the inspired blend of Leto’s commands and Ixian imagination made the structure conceivable. One hundred and fifty metres in diameter, the tower sat on a foundation which plunged as deeply under the sand as it climbed above. The magic of plasteel and superlight alloys kept it supple in the wind and resistant to sandblast abrasions.

Leto enjoyed the place so much that he rationed his visits, making up a long list of personal rules which had to be met. The rules added up to “Great Necessity”.

For a few moments while he lay there he could shed the loads of the Golden Path. Moneo, good and reliable Moneo, would see that Siona arrived promptly just at nightfall. Leto had a full day in which to relax and think, to play and pretend that he possessed no cares, to drink up the raw sustenance of the earth in a feeding frenzy which he could never indulge in at Onn or at the Citadel. In those places, he was required to confine himself to furtive burrowings through narrow passages where only prescient caution kept him from encountering water pockets. Here, though, he could race through the sand and across it, feed and grow strong.

Sand crunched beneath him as he rolled, flexing his body in pure animal enjoyment. He could feel his worm-self being restored, an electric sensation which sent messages of health all through him.

The sun was well above the horizon now, painting a golden line up the side of the tower. There was the smell of bitter dust in the air and an odour of distant spiny plants which had responded to the morning’s trace dew. Gently at first, then more rapidly, he moved out in a wide circle around the tower, thinking about Siona as he went.

There could be no more delays. She had to be tested. Moneo knew this as well as Leto did.

Just that morning, Moneo had said: “Lord, there is terrible violence in her.”