Despite the disturbance in the night, Chrístõ and his brother were awake just after dawn and enjoyed a rehydrated breakfast before striking camp and heading into the woods at the foot of Mount Perdition. The path began to rise steeply almost at once but they pressed on. Garrick was ready as always to prove himself equal to his older brother and never complained of tiredness.

“Red firs are unique to this one place on our world,” Chrístõ told him, the didactic streak in him always to the fore. “They are highly desired by garden planners who would like to have the blazing red colour in the arboretums of the great demesnes, but the Oakdae?e family guarded them jealously and besides, they don’t transplant well. The volcanic soil of Mount Perdition suits them best.”

“I didn’t know you knew about trees,” Garrick pointed out.

“Epsilon used to brag about them when we were at the Academy. He had a bonsai tree with carmine leaves and tiny red pine cones that he would show off to anyone whether they cared or not. The fact that his family’s land contained something unique was a source of pride to him.”

Garrick knew about his older brother’s arch-nemesis and his ignominious fate, though not in full detail. The former Oakdae?e heir’s crimes were far too ugly for an eight year old to know about, even one about to face the Untempered Schism.

“Cal owns the trees now,” Chrístõ added. “Which would make Eps very angry if he knew. But fortunately, prisoners on Shada don’t get visitors.”

He suppressed a shudder at the mention of Shada. He didn’t even like speaking of it in jest. Garrick looked at him but shrewdly said nothing. His lessons about the history of Gallifrey had touched on that dark place occasionally, but Epsilon was the only person anyone in his family knew who was sent there.

“Never mind him. The sun is shining and the trees are glittering red above us. Let’s press on. I’ll teach you the Prydonian fighting song as we go.”

Garrick laughed as Chrístõ taught him the lyrics to the rather disreputable song with at least fifteen verses, each more rowdy than the previous one, sung by spectators at inter-Academy sporting events. The tune was far from great composition. On Earth an almost identical tune went with an equally raucous set of lyrics about the Scottish national football team. That was one of those coincidences that made the universe an interesting place.

Garrick learnt to sing the song in a sweet-pitched voice that didn’t quite harmonise with his brother’s soft lyric baritone. Not that Chrístõ was paying much attention to such things. The Prydonian Fighting Song was meant for singing loudly, not prettily. Their voices rang out through the forest and there was nobody else to criticise them. They may have sent some birds and small mammals scurrying away in fright, but they pressed on and nature could resume its natural course in their wake.

They came to the edge of the forest about the thirteenth hour, midday on Gallifrey with its twenty-six hour day. Chrístõ made a temporary camp in the shade of the trees with a groundsheet beneath them to spread out their rehydrated lunch. He supplemented their rehydrated chocolate dessert with a handful of pine nuts that he had collected. Their sweet, nutty and above all authentic taste complemented the artificial cocoa taste of the pudding.

“It’s the last natural food we’ll have for a bit,” Chrístõ admitted. “Nothing edible grows up on the mountain. Not even ground cheese can take root on Perdition. It’s just too acidic.”

“Isn’t Mount Lœng an extinct volcano, too?” Garrick pointed out as they rested from their lunch and waited for the hottest hour to pass.

“Mount Lœng is a much older volcano, long expended,” Chrístõ answered. “It hasn’t erupted for at least ten thousand years. Perdition is technically only dormant. There is every possibility it will erupt in the next half millennia.”

Garrick looked worried.

“I said half-millennia. There is no danger of it happening in the next half day. There would be a great many seismic indicators if there was going to be an eruption. Even the caldera is buried under centuries of cooling magma – and that is beneath thousands of metres of igneous rock. It would take a mighty explosive force to open it up again. And that’s CERTAINLY not happening while we’re on the mountain.”

He wasn’t sure if Garrick was disappointed about that, but imagining what would happen if such an explosion occurred, blowing out the side of Perdition with a mighty pyroclastic cloud of dust, steam and ash, laying the forest to waste even before the lava began to escape from its subterranean prison made his brown eyes wide, round and bright. Thinking about it was as close as he needed to get to such a thing.

“There are some active volcanoes on Earth. I should show you some time – maybe when you’re a BIT older. Meanwhile, let’s press on up the scar.”

They were exposed to the sun now that they were out of the forest and climbing the remnant of the last volcanic eruption from Perdition. Chrístõ rubbed sun block on Garrick’s face and neck. He was as pale complexioned as his older brother and didn’t yet have fully regenerative cells. He would burn before he tanned even under Gallifrey’s sun which had its harmful rays filtered by a thick and effective ozone layer. Sunburn would make camping an unpleasant experience for an eight year old.

Chrístõ felt the heat on his skin, but his cells continuously repaired the damage and he stayed pale beneath a slight flush from the exertion of climbing an increasingly steep slope. The ground beneath them was far from smooth. The old lava had cooled and set in ribbons and whorls that they had to physically climb over at times. Even over a thousand years there had been very little erosion of the hard, unyielding rock and only here and there, in the cracks and crevices was there an accumulation of hard gravel and dust that might, in another thousand years, if the promised eruption didn’t occur, start to qualify as topsoil.

Even so, life had gained a slight foothold. The more sheltered of the crevices, where rainwater might not evaporate easily, had also sheltered seeds that blew in the wind. A ragged plant with small pink-red flowers grew in those places.

And on the rock itself, there was a very thin layer of fungal growth – micro-millimetres thick but spreading a reddish tinge across the bare rock that could be seen in a certain light. It would, one day, perhaps, be thick enough and red enough to add another dimension of colour to the scar. But that was a long way off, yet.

“How much further to the cave?” Garrick asked when they stopped for tea at five o’clock. He looked up towards the peak. It was much closer now, though not close enough for the boy.

“We’ll reach the cave entrance about dusk,” Chrístõ answered. Garrick looked disappointed. His brother knew why.

“We’ll be ready for supper by then. We’ll eat, and then we’ll bring plenty of gravity globes and go look for diamonds in the cavern.”

“It won’t be bedtime?”

“We don’t need to put up the tent inside the cave. Bedrolls can go on the floor. That saves some time. Plus it makes no difference whether it is night or day inside the mountain. We’ll explore caves and hunt for diamonds for as long as you can keep from yawning.”

“Did mama say I could stay up late?”

“Your mother said I was in charge of you until we get back. I say you can stay up late. Besides, you’re nearly a Candidate. Bedtimes are optional for Time Lords.”

“Nobody tells you when to go to bed?”

“I tell myself when to go. I know when I’m tired and need to sleep. Especially when I have work to do in the morning. But we don’t have anything special to do tomorrow except find more diamonds. We can sleep late.”

The flexibility of routine pleased Garrick as much as the prospect of reaching the caves in a few hours. They were pleasant hours, too, as the sun began to drop low. The scar was in shadow long before sunset and Humphrey was able to come out of his backpack and bowl along, sometimes invisible against the blackness of the rocky outcrops except for his wide eyes and slit mouth.

“Humphrey is excited. He knows we’re going to a cave,” Garrick confirmed.

“Cavvve,” Humphrey added and trilled joyously.

“We should teach Humphrey the Prydonian Fight Song,” Chrístõ suggested.

“I don’t think he can SAY Prydonian,” Garrick pointed out. His attempts at such a polysyllabic made them both laugh and made Humphrey even happier as he fed off their cheerful emotions.

Humphrey reached the cave before the two brothers. They could hear his excited trilling echoing strangely as they climbed the last steep quarter mile, clambering over some of the roughest parts of the scar. When they reached the cave entrance he was bowling around excitedly, in his own natural environment again.

“Don’t get cheeky,” Chrístõ told him as he shrugged off his pack and unrolled the spongy ground sheet for a sitting area and a place to eat their evening meal. There was still some light from outside, but when he launched a gravity globe with its warm yellow light it looked dark outside by contrast. He unpacked the food rations for this meal – chicken soup, creamy ham carbonara and treacle tart with cream for dessert. The tastes were never quite completely right, but the hot food was welcome as the sun set and the temperature dropped up here close to the snow line. They had cocoa afterwards before Garrick could wait no longer and they had to go in search of diamonds.

“Dowwwwnnn,” Humphrey insisted.

“How would you know?” Chrístõ challenged him. “You’ve never been here before.”

“Doowwwnnnn,” Humphrey said again and hovered at the back of the cave like a dog impatient for the off.

As it happened, he was right. The tunnel near the back of the cave did go down very steeply almost immediately. Humphrey was ahead, with Garrick behind him. Chrístõ was slower because the tunnel roof was barely five and a half foot from the floor and he had to stoop. At least he was unencumbered by a heavy pack. He had brought a rucksack with some rope and other equipment in case they had to repel down any slopes, and a supply of Kendal Mint Cake just to keep Garrick happy, but otherwise his load was light.

They had gone about a quarter mile in simple linear distance when the tunnel began to be part of a honeycomb of similar tunnels, some too small even for Garrick to contemplate exploring, some narrow cracks, others turning into dead ends very quickly. Humphrey tried some of those. Chrístõ was following a map that was in his head.

Cal had given him exact instructions about how to get to the diamond cavern. He knew they were on the right track, in any case, because he could FEEL the jewels not far away. It was an extra-sensory trick Time Lords had learnt generations ago when mineral ores had become their source of wealth. The most sensitive of them could FEEL the presence of gold, silver or diamonds. There was a different sensation for each. Gold was like heat, silver a sharpness. Diamond felt like ice cold splinters in his brain. They all gave him a migraine if he concentrated too hard. That was the drawback, and the reason few Time Lords had ever aspired to be psychic mineral prospectors, but he could filter the sensation so that it didn’t hurt too much.

Humphrey was absent for a while. The honeycombing was so extreme that he had gone exploring deep into the bedrock of the mountain. He emerged again with a wide grin and a hug and told Chrístõ that the big shiny cave was up ahead. He wanted him to follow through one of the smaller tunnels, but that was impossible. He simply wouldn’t fit.

“I can,” Garrick said, shining his torch into the tunnel. “Can I explore with Humphrey? He said it went to the diamond cave, so I’ll be all right. I’ll meet you there.”

All his instincts said no. Chrístõ didn’t want to lose his brother in a catacomb of tunnels too small for him to effect a rescue. But the boy was excited about the idea of going off on his own.

“Humphrey, you stick with him,” he said sternly. “Don’t let him out of your sight. Garrick, stay in mental contact with me. If there is anything at all that bothers you, tell me right away.”

With that one injunction he let Garrick go on his own mini expedition while he followed the main tunnel. He felt Garrick’s voice in his head all the time, telling him about the even smaller tunnels that led off from the one he was following.

“None of them really ARE tunnels as such,” Chrístõ explained. “It’s the cooling of magma forming hundreds, thousands of lava tubes as the hot stuff escaped leaving spaces behind. Then erosion did the rest, water getting into cracks, forcing them to widen. There’s probably a subterranean lake somewhere deep beneath the mountain from a thousand years of rain and snow seeping down.”

“I wish we could see that,” Garrick said.

“Well, we can’t, not this trip. Besides, we don’t even know if there is a way down other than the actual main conduit, and that would need more rope than we’ve got with us.”

It would need a TARDIS, Chrístõ thought. Or some other ‘cheat’ rather than traditional spelunking techniques. Maybe another time.

He reached the cavern before Garrick did. His route through what had been, once, a major branch pipe from the conduit, was more direct than the wanderings through smaller ways. He knew his half-brother was on his way, though. He was still commentating on the passages he was moving through.

“Come on,” Chrístõ told him as he sent up a gravity globe to light the cavern. “Or I’ll get all of the diamonds.”

Even if he had a sack with TARDIS like properties he couldn’t do that. There were diamonds all around him. They glittered in the walls and ceiling of the cavern and lay about on the floor as if somebody had just scattered them carelessly. He picked one up idly. It was the size of his fist and glittered brightly even though it was uncut and unpolished. If it had been good quality it would be priceless, but there were just too many flaws in it. He held it up to his eye and looked at them – microscopic cracks all through the diamond like a three-dimensional map of a glass world.

Garrick emerged from a narrow crack in the wall, barely wide enough for him to get through. Humphrey came after him whistling with joy after his exploration of the sort of dark places he came from.

“Ohhhh!” Garrick looked around the cavern. He, too, reached to pick up the first diamond he spotted. Again, it was a nearly worthless one, but he didn’t care. He thrust it into his pocket and reached for another.

“Take your time,” Chrístõ told him. “Look for the better ones. There’s a whole cavern floor full of them.”

Chrístõ cleared diamonds from a section of the floor and sat down while his brother joyfully explored, picking up and examining diamonds, rejecting some, putting some in his pockets. Soon his jacket was starting to look very bulky and lumpy.

Humphrey wasn’t interested in diamonds, and huge brightly lit caverns didn’t suit him. He was having fun exploring the honeycomb of passages in the walls.

“Chrístõ!” Garrick’s urgent call had him back on his feet again. He rushed towards his brother, who was standing very still on the edge of a sudden hole in the floor. His back was to him, but Chrístõ knew he was scared.

“It cracked and disappeared,” he said. “I was just trying to reach this really big diamond and….”

“Is the bit you’re standing on cracking?” Chrístõ asked. He stopped a few strides away from his brother as he realised the problem. The cavern floor was thick, solid metamorphic shale but in this part, it wasn’t thick. It looked as if it was wafer thin. Even Garrick’s slight weight had broken it.

“Yes. I can hear it. I’m scared. I don’t know what to do. If I fall through… I’ll end up in the magma chamber.”

“You’ll hit the lake, first. But we’re not even going there. Garrick, take one small step backwards towards me. Just move one foot.”

Garrick slowly lifted one foot and put it back. There was an audible crack. He was far from safe.

“Now the other foot,” Chrístõ told him. “Keep coming, slowly.”

“I don’t think I can,” Garrick answered. He had taken two steps and the ground was breaking under both feet, still.

“Garrick, close your eyes and think of gravity,” Chrístõ told him. “Think of the forces that keep you pressed to the ground. Then remind those forces that you are very nearly a Time Lord candidate. Gravity, like time and space, belong to you. They obey you.”

“I… am trying.”

“Yes, you ARE,” Chrístõ assured him. “NOW come towards me.”

Garrick hardly knew he was doing it, but he was already levitating an inch above the ground – and an inch was more than enough. He was no longer standing on the weak shale layer. He drifted towards his brother who grabbed him and moved further back before sinking to the ground and hugging him tightly.

“You did it, kiddo,” he said. “I’m proud of you. The first time I levitated I blacked out for twenty minutes afterwards. Now, stay clear of that section of the floor. Stick to the other end of the cavern until I’ve mapped it out with the sonic and worked out how far the dangerous bit extends.”

“I got the big diamond,” Garrick pointed out, holding up a huge shining rock, almost a perfect lozenge shape. It was as big as Chrístõ’s open hand and when he looked at it carefully he could actually see no flaws at all.

“Put that one deep in your pocket,” he told his half-brother. “I think it might be a good one. It would need a closer examination, but it might be the one in a million flawless diamond in this cave.”

Garrick was thrilled. He put it carefully into one of the zip-up pockets of his jacket. He was ready to go on with his quest for interesting though flawed diamonds for his collection when Humphrey suddenly shot out of one of the honeycomb cracks.

“Badddddd,” he wailed. “Baddddddd man.”

“What?” Chrístõ reached out his hand to Garrick and drew him close. “Humphrey, what do you mean? We’re alone here.”

“Baddddd mannnn…. Innnn cavvvvvvvvve.”

“He saw somebody,” Garrick said, reaching out his hand through Humphrey’s darkness. “There was a hole in the tunnel… and it looked into a cave that somebody was living in… there was a mat and a lamp….”

Chrístõ had never been able to fully read what passed for Humphrey’s mind. Perhaps Garrick was better able to reach into it because his child mind, not yet encumbered by the Untempered Schism, was less complicated and closer to the darkness creature’s simplicity.

“Then a face looked back at Humphrey and it scared him. He ran away.”

“A cave with no way out?” Chrístõ was puzzled.

Then the answer to the puzzle literally materialised in front of him. Somebody with a time ring could easily get into a cave without entrances. That somebody wore a black cloak with the symbol of Oakdae?e on the clasp. It was a servant’s cloak – belonging to one who had worked for Lady Oakdae?e, or even her long dead husband.

A man who was still faithful to the House of Oakdae?e.

“Thieves, trespassers,” the man cried, his eyes wide with anger as he flew at Chrístõ. Garrick screamed as his brother pushed him aside and adopted a Sun Ko Du stance ready to fight him. Humphrey keened mournfully as the hand to hand battle ensued. The servant knew a little martial arts, though he was far from fully trained. He was strong, and he was mad, which lent him extra impetus. Chrístõ knew he would not be easily defeated.

But defeat him he must, because this man was prepared to fight to the death. He saw the flash of steel in his enemy’s hand and managed to knock the knife away before he could stab at him. He saw Garrick reach and throw it towards the hole in the ground. He missed. The knife landed on the thin crust of shale surrounded by an ever expanding network of micro-cracks.

“Your Master is long dead,” Chrístõ told the madman. “So is your Mistress. And their son is locked away on Shada. The new Master of the Oakdae?e lands is a friend of mine. He never sent you here.”

“There is no new Master of Oakdae?e. The usurper will die along with all trespassers and thieves. The diamonds of Mount Perdition will not belong to the enemies of his House.”

“You’re here to protect these diamonds?” Chrístõ was astonished. The diamonds were almost all worthless, yet this man, if Humphrey’s account of his living space was to be believed, had made himself into a kind of anchorite, holed up in the mountain, simply to stop anyone taking them.

“They belong to my Master. I will not let the usurper have them.”

“You are completely MAD!” Chrístõ told him. “Completely off your rocker.”

That was obviously true, but the servant of Oakdae?e was still prepared to fight to the death.

And he meant it to be Chrístõ’s death. He saw the danger at once. The madman had edged around until they were both on the edge of the thin shale. Chrístõ felt the ground cracking beneath him as the servant attacked again. They both fell onto the place that had barely held up Garrick. The boy screamed with almost the same pitch as the cracking shale as they fell through the widening hole.

“Chrístõ!” Garrick’s anguished cry echoed around the cavern as he saw his brother disappear into the black gulf. Then he heard a joyous sound. Chrístõ called back to him.

“I’m alive,” he assured him. Then Garrick saw his brother clamber up out of the hole and slide himself across the still dangerously cracked section until he reached safe ground. “You’re not the only one who can make gravity obey you. It only did so for a few seconds. I wasn’t exactly concentrating, but it was long enough to get a handhold. It’s not the main vent, just another offshoot, but its deep enough.”

“Is he dead?” Garrick asked.

Chrístõ wasn’t sure. He hadn’t exactly been concentrating on that, either, but he was sure the Doppler sound of the scream had been cut off before the body reached the bottom of the side vent.

He had a time ring. He could transport himself to safety.

The servant of Oakdae?e might still be alive and madder than ever in his quest to protect the mountain from thieves and usurpers.

“Garrick,” he said. “I think we are going to have to cut our trip short. We’re not safe here. Do you have enough diamonds to be going on with?”

“Yes,” Garrick answered, patting his bulging pockets. “But we’re in the mountain. How do we get home?”

Chrístõ took his TARDIS key from his pocket.

“They call this deus ex machina in films,” he said. “But just in case we had any accidents, falling down the mountain or something, or you just got tired, I upgraded the remote materialisation control on the TARDIS. If it works inside here….”

For a horrible moment, after offering Garrick the promise of escape, he thought it wasn’t going to work. It hadn’t functioned for years and he hadn’t fully tested the repair. He had to hope it would hold just this one time, at least.

Just at the last moment when he began to think he had trapped himself and his brother in the mountain with a dangerous fanatic at large, he heard the familiar sound of the TARDIS materialising. It kept its default form as it solidified before him.

“It worked.” He breathed a deep sigh of relief as Humphrey emerged from the shadows and bowled towards the door. He held his brother’s hand tightly until they were safely inside, beyond the reach of a time ring.

Valena came running as the TARDIS materialised in the hall. The boys were not due back from their trip for two more days. Something had to be wrong. When Garrick came running out of the door with a huge diamond to give her as a present she was relieved, but there was an expression on her stepson’s face that told her that something had happened.

“Garrick is all right,” Chrístõ assured her. “I promised I would look after him. But I need to speak to my father. Is he in his study?”

Valena nodded. Chrístõ took his leave of her and went to his father. He told him everything from the disturbance in the night when Garrick thought somebody was there to Humphrey’s discovery of the anchorite cell with no physical way in, to his final showdown with the Servant of Oakdae?e.

“You think this man is still alive?”

“I do,” Chrístõ confirmed. “I think he used the time ring as he fell. He is out there, resenting all usurpers of the Oakdae?e House. Garrick and I trespassed on the mountain he considered to be under his guard, but I rather think we’re not the main targets of his anger. Cal is the one likely to be in most danger.”

“He is safe for now, with Maestro and the Brotherhood. But he is due to go to the Untempered Schism next month as well as Garrick, and after that it is hoped by all with any interest in the matter that he would take his place as Master of the House of Oakdae?e and the property that is rightfully his. We shall all have to be on our guard against this madman on his behalf.”

“Yes,” Chrístõ agreed.

“It will be put in hand. Between your friend, Director Hext and some of the favours I can call in we shall assure Cal’s ascension to the great Oldblood Patriarchy. Meanwhile, is Garrick all right? Is he disappointed by the way his field trip ended?”

“I think he’s rather pleased about it all, actually. He got to see me in action hero mode, and he has a rather interesting souvenir he will be wanting you to see as soon as possible.”

“Then let’s not make him wait any longer.” Chrístõ saw the smile in his father’s eyes – pride in his elder son who had saved the day, and joy in the younger one’s childish enthusiasms. All other concerns were put aside for another day.

But that other day would dawn before long.