"The Tree at the End of the World," said the Doctor softly. "Idas, where are we?"
Idas studied the map for a moment, then pointed.
"Here," he said confidently.
"Good. And where is the Citadel where they"re keeping your father?"
Idas pointed to a squarish shape at the centre of the map.
"I see," said the Doctor thoughtfully. "Now, how can we get from where we are to the Citadel-quickly?"
Idas hesitated. "There is a way-but it is forbidden."
"Why?"
"It is guarded by invisible dragons. Not even the Guards are allowed to use it. Only the Seers-and they have special powers."
The Doctor chuckled. "So do I, Idas. So do I. Anyway, the Tree at the End of the World is always guarded by dragons. Fire dragons with tongues of flame!"
Idas shuddered.
"Do not worry," said Leela. "The Doctor has killed dragons before!"
Jackson and his crew were resting at yet another junction.
They felt weary and defeated. The mysterious disappearance of the smoke had removed one danger, but after endless searching they still hadn"t managed to locate the P7E.
Herrick leaped to his feet, raising his shield gun.
"Something"s coming-following us along the tunnel."
They waited tensely. A squat metallic shape rounded the tunnel and came gliding towards them.
"It"s that robot dog of the Doctor"s," said Jackson, amazed. "What"s it doing here?"
K9 glided to a halt. "I bring instructions from the Doctor," he said importantly. "You will accompany me at once, please!"
"Why should we go with you?" demanded Merrick angrily. "We"ve got to find the P7E."
"I have already located the P7E. The Doctor is on the way there now. Please follow me."
K9 wheeled and set off back down the tunnel. The Minyan crew looked at each other, and then followed obediently. There didn"t seem anything else to do.
Idas led the Doctor and Leela down a short dead-end tunnel. It ended in a wall of rock in which were set two ma.s.sive metal doors.
The Doctor took a step forward. Idas pulled him back.
"No, Doctor, that"s where the dragons live."
"It is, is it? Let"s see if they"re at home." The Doctor took an apple from his pocket and handed it to Leela, who took a bite out of it.
"Don"t eat it," ordered the Doctor. "Throw it!" Leela tossed the apple towards the door. A lattice-work of lightning flickered across the tunnel, reducing the apple to charred fragments.
The Doctor produced another apple. "Look for the source-point this time, Leela. The mouth of the dragon."
He tossed the apple, the lightning flickered again, and this time Leela saw the side nozzles projecting the maser-rays.
"Got it, Doctor."
"Right, give them a blast!"
Leela raised her shield gun and blasted the nozzles, first one side and then the other, turning them into lumps of shapeless metal.
"Now the door!"
A long blast from the shield gun melted the door into nothingness, revealing a square chasm, rather like a lift-shaft.
"In you go," said the Doctor cheerfully.
Leela went cautiously up to the edge. It was like a lift-shaft all right-but where was the lift? All she could see was a dizzying drop, stretching down and down. "Oh, no, Doctor, there"s nothing there!"
"Oh yes there is. There"s gravity."
Leela looked suspiciously at him. "Didn"t you once tell me gravity makes things fall?"
"That"s right-towards the centre. But this is a new-born planet, Leela, on the very edge of creation. Things are different here. We"re almost at the centre of the planet.
Inside this shaft there will be zero gravity, just as in s.p.a.ce.
That"s my theory, anyway."
"But it"s just a theory?"
"That"s right," said the Doctor cheerfully. "So I"d better test it!"
He stepped over the edge of the shaft-and stood suspended in nothingness.
Leela turned to Idas. "Come on," she said with resignation, and dragged him bodily into the shaft.
All three hung suspended in s.p.a.ce.
"How do we move?" asked Leela.
The Doctor grinned. "Just push!"
"Push?"
The Doctor nodded. He stretched out until he could reach the side of the shaft, pushed upwards and immediately began drifting down. His voice floated up to them. "Push! "
Leela turned to Idas. "Push!" she said fiercely.
Now all three were floating down together.
"You all right, Idas?" called the Doctor.
Idas nodded, paralysed with fear.
They drifted down, down, down... It was a pleasant enough sensation, decided Leela. But what happened when they reached the bottom?
Absorbed in the new sensation, none of them noticed a spy camera set into the wall of the shaft.
On his monitor screen, Tarn watched the three figures drifting down past the camera"s field of vision. Just as he"d suspected-aliens. Two aliens, and a traitor Trog.
He leaned forward to the communications mike. "Gate patrol-alert! We are being attacked by alien invaders.
Prepare an ambush."
Tarn sat back, well satisfied. When the invaders reached the gates of the Citadel, they would die.
Chapter Ten.
The Sword of Sacrifice In the temple which had once been a s.p.a.ce ship, everything was ready.
A crowd of ragged slave workers huddled at the back of the huge room, flanked by armed Guards.
There was a murmur of awe as Lakh, the Seer, strode into the temple and bowed low before the screen of flickering light that was the visible manifestation of the Oracle-the G.o.d whose presence pervaded the entire temple, the one who had ruled since time began.
Ankh came and ranged himself beside his fellow Seer, bowing low.
The Oracle spoke, its voice a throaty whisper filled with infinite age and wisdom. "Is the time right?"
Lakh bowed again. "The time is right."
"Is the slave ready?"
"The slave is ready."
"And those who watch?"
"They are filled with fear."
The questions were part of the time-hallowed ritual of sacrifice.
The dreadful voice whispered, "Let the sword ask its question."
"It shall be done!"
Black-hooded Guards pushed forward the trolley to which Idmon was fastened, positioning it in the exact centre of the temple.
Idmon stared upwards, knowing what he would see.
Suspended above him was an enormous sword, its needle-sharp point poised above his heart.
The sword was suspended by a silken cord, and the cord ran through two ring bolts in the ceiling. Suspended a little below the tautly-stretched cord was a ceremonial oil-lamp with a tiny naked flame.
It only remained to wait.
In time the cord would char and fray in the rising heat.
When the cord snapped, the sword would fall, and Idmon would die.
But not for some time yet. The lamp was some way below the cord, and its flame was turned low. The longer the wait, the greater the opportunity for the victim-and the audience-to reflect on the folly and wickedness of rebellion.
Idrnon stared up at the gleaming sword-point and thought about his son, wondering if the boy had got away.
Lakh turned towards the watching slaves, raised his hands and began the ritual.
"Lamp burn, sword fall.
Ask the question that hangs over all."
The crowd took up the chant. "Ask the question that hangs over all."
"... Eventually the flame burns through the rope, and the sword falls," said Idas. His face twisted in grief, as he thought of his father.
They were still drifting down the shaft, though the bottom, was now in sight.
"It is a very complicated way to kill," said Leela. "Why go to so much trouble?"
"Terror," said the Doctor simply. "Intimidation! The more ritual and mumbo-jumbo, the greater the effect.