Christo was drinking a morning coffee outside a cafe by the marina of the city of Ponta Delgada on the island of São Miguel in the Azores. The sun was still low and only a few early risers were awake, yet. If he cast his mind around he could feel sleeping souls in many of the yachts. A few were waking and thinking about breakfast. The only people fully awake were the waiters in the seafront cafes who were there to provide those breakfasts and who had risen much earlier.

One of those yachts wasn’t a real yacht, of course. The TARDIS had disguised itself as a sleek blue and white pleasure craft moored close to the cafe amenities. Beyond the harbour wall in deeper water the RSV Wayfarer was anchored. He and Garrick had dined aboard last night with the University of Ireland research team that included his friend Riley Davenport as their photo-archivist. They were in the Azores exploring yet another underwater site that COULD have inspired ancient legends of Atlantis.

Today they were taking a day off from diving in the deep Atlantic and were going to dive in an inland lake instead, just for fun, and ignoring all jokes about a Busman’s holiday.

Garrick appeared on the deck of the TARDIS yacht and hurried to join his brother. A barista brought him coffee and bread rolls. He looked sleepy and a bit tousled and Christo couldn’t resist mentioning it.

“I wasn't doing anything wrong,” the boy said defensively. “I was skyping to Sean O’Brien until really late. I forgot that midnight is only twelve o'clock on Earth, not thirteen and time got away from me.”

“Not a problem a Time Lord should ever admit to,” Christo noted. “You talked to Sean all through dinner. Why did you need to Skype all night?”

“I was interested in some things he knows about the archaeological history of these islands. And I know now why we came to join them all here.”

Garrick smiled mysteriously. Christo wasn’t sure why for the moment.

“We came because I’ve never actually been to the Azores and when I heard from Riley that they were out here it sounded like a great place to catch up with our friends. There's no mystery.”

“What about the advanced race that might have helped ancient humans cross their oceans?”

Christo still had no idea what his brother was talking about. He invited him to explain.

“There are these stories that, way before humans knew about navigation, longitude and latitude, any of that sort of thing, primitive tribes from....”

Garrick paused to recall a place name he had only just heard.

“Fonn... Foneshea?”

“Phoenicia,” Christo corrected him. “The people who conquered a lot of North Africa in ancient times. The other side of the Mediterranean to where we were in Greece and Italy when we joined up with the Wayfarer crew last year.”

“Well, anyway... These people are alleged to have used these islands as a stopping off point to get to the continent right on the other side of this ocean at a time when humans weren’t advanced enough to do that. And Colm came in on the Skype at one point and he says that an Irish expedition in primitive boats might also have reached the ‘New World' in a similar way, even though the history books say that Europeans didn’t get there until the fifteenth century.”

It had actually taken him a bit of trouble to understand that “New World” in that context didn’t mean another planet, but he was intrigued by the possibility that aliens to Earth, perhaps from a technologically superior planet like their own, had been involved in the advancement of Human exploration of their world.

“Colm is talking about the legend of the Brendan Voyages,” Christo said. “That would be a bit later – about seven or eight hundred years after the Phoenician Empire. And I don’t think their route came near the Azores. I think it went to the north via Greenland and finished up in Canada. The Phoenicians would probably have used these islands to stock up on food and water and aimed for the south American lands.”

Garrick was getting confused now about the Americas. Christo smiled indulgently.

“Well, this is exactly the sort of educational thing father envisaged me doing with you. Psychic Geography 101. Close your eyes and get a fix on this planet in your mind. Now find the Americas. Two huge continents joined by the relatively narrow Isthmus of Central America. In this time North America is occupied by the two huge countries of Canada and the USA, South America is divided into twelve countries and four dependent territories. Central America and the Caribbean islands are....”

Garrick’s mind worked in a way the makers of Google Earth could only dream of as he heard his brother’s voice and focussed on each part of the Americas in turn, then widened out as Christo illustrated how the legendary Irish sailors, led by the man speculative history if not a more factual kind remembered as Saint Brendan the Navigator, patron saint of sailors, had taken the cold route across the North Atlantic.

“I don’t know for certain if that story is true,” Christo added. “There are words used in First Nation dialects that closely correspond to the Gaelic those sixth century Irish would have spoken, and other little clues that they made it, but the evidence has been challenged at many levels and it might just be a nice story. The stories of the Phoenician travellers seven centuries before are based on stone age artefacts in South America that are similar to artefacts found in North Africa and possibly on these islands, which would make perfect sense if the sailors came here on the way.”

“And they did that?”

“Again, it is more legend than historical fact, “ Christo admitted. “I wouldn’t completely dismiss the possibility that travellers from Europe or Africa made it here, at least. Its only about a thousand miles, give or take. Establishing communities here is feasible. The other two thousand miles to America is the hard part. Food and water for that long a journey wouldn't be easy.”

“So... Why did the government that rules these islands.... Portu....”

“Portugal... On the Iberian Peninsula along with Spain and San Marino, “ Christo told his brother helpfully. The boy visualised Iberia and then fixed the Azores in relation to it.

“Why was the government of Portugal opposed to archaeological exploration of the islands to prove that those primitive people came here?”

“I wasn’t aware that they were opposed to it,” Christo answered.

“Sean told me it used to be really hard to get permits and some of the proof that the islands were occupied was dismissed altogether by a government investigation. They said the artefacts were just natural rock formations.”

“Then at a guess, I’d say it was because until very recently in its history Portugal was a deeply conservative and Catholic country and a fundamental belief in the superiority of the fifteenth century Portuguese seafarers and explorers who discovered new territories and gave Portugal its overseas empire was important to them. The idea that primitive people from north Africa had reached this far long before them upset that certainty.”

“You mean... It was all down to pride and jealousy?”

“Maybe a touch of latent racism, too,” Christo added. “Europeans have always tended to think of themselves as better than Africans.” He saw his brother’s expression and laughed. “We come from a society that thinks it is superior to everyone else in the universe, so we can’t claim any moral high ground, there. But it really is the simple explanation of why evidence of primitive human exploration of the Azores might have been suppressed.”

Garrick considered that explanation carefully and it seemed to satisfy him.

Except...

“Sean O'Brien has another theory, though,” he said. “He thinks there could be evidence of extra-terrestrial visitors to be found on these islands and the Portuguese government covered THAT up.”

“A conservative, deeply religious society would probably want to do that, too,” Christo told him. “Think what knowing there ARE superior races out there in the galaxy would do to their belief in themselves. But Sean is a hopeless conspiracy theorist. He believed in alien visitors to Earth even before I met him. I've managed to convince him that aliens had nothing to do with either the pyramids of Egypt or Mesoamerica, the temple complex of Machu Picchu, Stonehenge, the Nazca lines and anything that happened or didn’t happen in Roswell, New Mexico. As for this mystery... When the anthropologists talked about advanced technology they just meant that the Phoenicians themselves were more advanced than previously believed. Their ship building methods and their grasp of celestial navigation were better than anyone supposed and they dared to travel further than those mostly European researchers had anticipated. No mystery, I’m afraid. Just a misunderstanding of history.”

Garrick looked disappointed.

“Did you WANT an alien conspiracy?”

“I thought...” Garrick shrugged. He wasn’t sure what he had thought.

“If you want alien interference in human history you need to look at Ancient Greece. The reason their alphabet is a lot like Gallifreyan is down to a bunch of Prydonian seniors who pretended to be gods and manipulated a whole society until they were caught and sent home in disgrace. You'll probably hear about that as after dark dorm gossip, but don’t ask any of your tutors to elaborate. They regard it as a black mark on the Prydonian honour.”

Garrick smiled wryly. He still wasn’t sure how he felt about his impending school life.

At least he didn’t have to think about that, yet. He had another cup of coffee and a plate of freshly baked bread rolls and cream cheese which constituted a light breakfast. By the time he was done their friends from the Wayfarer had arrived and they all piled into two Land Rovers hired to take them into the interior of the island.

Colm Sullivan, Riley Davenport and Sean O’Brien were with Christo and Garrick in one of the cars heading towards one of the famous caldera lakes that drew tourists and archaeologists alike to São Miguel and its sister islands.

“I hear you’ve been putting ideas into my naïve little brother's head,” Christo said to Sean as the cars wound around narrow inland roads that predated the internal combustion engine by at least a century.

“Ideas?” Sean queried as Garrick winced at the words ‘little' and ‘naïve’ used about him.

“About alien interference in Human navigation of the Atlantic.”

Sean gamely stood by his Fortean Times version of Azores history. Christo smiled and shook his head.

“Sorry, but this is yet another case of imagination running ahead of itself. I can assure you that Garrick and I are the first aliens to have set foot on this island. Or claw, tentacle, feeler or other appendage.”

Sean still stuck to his beliefs. Christo let him. They were his beliefs and it wasn’t his job to disabuse him. Besides, he and Garrick only proved his point. They WERE aliens from another world, just disappointingly Human looking and without any sinister intent.

Mostly he and Garrick were there to enjoy the beautiful and unique island scenery just like everyone else. The Azores were created by ancient tectonic activity. Volcanoes which were still listed as dormant rather than the more reassuring ‘extinct' formed most of the uplands. But that didn’t mean the islands were desolate grey moonscapes. Proximity to the gulf stream gave the Azores a warm but well watered climate, and the view as they climbed ever higher into the region called the Água de Pau Massif was impossible to describe without using the word ‘verdant’. Simply ‘green’ didn’t go far enough. Trees, bushes, plants with flowers of every colour, many varieties of grass, covered any part of the basalt bedrock where as much as a millimetre of topsoil had settled. Words like ‘tropical' and ‘paradise' also came to mind, even though the Azores were not actually ‘tropical’ islands. Even people as well travelled around the world as the Wayfarer researchers wouldn’t argue with such descriptions.

“One really big eruption would destroy it all, though,” Colm pointed out. “On an epochal scale, the Azores are here today, gone tomorrow. Pushed up by a meeting of three tectonic plates, any major seismic event could see them disappear back into the sea.”

“That's a cheerful thought,” Sean told him.

“It’s true, though,” Colm insisted.

“Well, that seismic event isn’t starting today,” Christo promised. “I checked the TARDIS sensors. No seismic problems around São Miguel due this week.”

“This week?” Riley queried. “You mean there might have been seismic problems last week - or next week – but we're safe this week?”

“We'd be safe next week,” Christo assured him. “We’re talking about micro quakes, registering on scientific instruments, nothing to disturb the fish, even.”

“Good, since we're diving, later,” Sean said. “Though it would be interesting to be underwater during a minor quake. I wonder if the fish would sense something happening before the electronic sensors. They detect all sorts of changes in the currents, after all. You would expect them to have some innate instinct – especially fish swimming in a collapsed caldera.”

The problems of measuring fish instincts against precision scientific instruments dominated the conversation after that, along with a question from Garrick about how fish got into a collapsed caldera lake in the first place. It was enough to stop anyone getting bored before they arrived at the side of Lagoa do Fogo, the Lake of Fire as it had been colourfully named.

“So how long has it been since Lagoa do Fogo actually WAS filled with magma?” Riley asked as those in the party with an interest and the skills for diving changed into scuba gear and launched the inflatable dinghy that would take them out into the deepest part of the lake.

“About fifteen thousand years,” Christo answered. “Though there was volcanic activity around the edges up to five thousand years ago. That’s three thousand years before your calendar counted up from year one AD, so its not a pressing issue for us, today, just a reminder that this planet is much older than many people think it is.”

“Why is Colm singing a song about a Lake of Fire under his breath?” Garrick asked as they launched the inflatable dinghy

Colm grinned and sang the chorus out loud, pleased that somebody had finally noticed the cultural coincidence.

“I’ll play you my Nirvana Unplugged CD later,” Christo answered his brother. “They do it rather better than Colm, who has a voice for folk music. Meantime, check your rebreather valves and adjust your face mask before we get ready to dive.”

Garrick knew the routine. He had been diving with the Wayfarer team before. It was one of those Human hobbies he had come to enjoy in the time he had spent with that race either on Earth or Beta Delta.

Diving in a caldera lake was a very different experience for everyone. Most of the researchers had spent their dive hours on ocean floors looking for sunken cities like Pavlopetri or several unnamed mystery ruins that might have been the fabled Atlantis. Mairead, the marine biologist and her partner, Anne-marie, also had extensive time, for work and leisure, on coral reefs.

They had all done some lake diving, but places like Loch Ness, Lough Neagh, or warmer and more romantic lakes like Geneva or Maggiore were quite different from this Lagoa do Fogo.

The wonderful clarity of the water that meant it was still amazingly bright close to the caldera floor was one difference.

Of course, being so high up what were the highest mountains in Europe when measured from the sea bed, and more than a thousand miles from any source of industrial pollution, the water quality was always going to be good. But the other reason for the clarity was the sort of lake it was.

All of those other lakes the team had experienced before were fed by rivers and streams that brought silt and plant litter with them. Caldera lakes were fed by rainwater and by water that seeped through the porous volcanic rock which filtered it very thoroughly.

Which is not to say they were lifeless. Where the porous rock hadn’t altered the PH balance of the water, plant and animal life would always find a way. And it was fascinatingly unique life because it had evolved in isolation from any other water system. Fish in most deep lakes were accustomed to darkness and were often eyeless. Here there was strong light all the way down and the flora and fauna could take advantage of it.

All this and the fact that the lake depths weren’t SO deep as to require decompression stops made for an exciting afternoon of leisure diving.

They returned to Ponta Delgada as the sun was setting towards a distant horizon and took up several tables at a seafront restaurant for dinner. They lingered afterwards for coffee and headed back to the marina near midnight.

“Sean,” Christo said when the group split, most of them heading to the dinghy to return to the Wayfarer while Christo and Garrick went towards the TARDIS yacht. “Come with us for half an hour. I can get you back to the boat, easy enough.”

Sean was surprised but intrigued. He was one of the few who were in on the secret but who had never been in the TARDIS. This was his chance. He waved to his friends and followed Christo and Garrick.

“Enjoy yourself,” Christo said to him. “Your first genuine alien ship. But if my suspicions are right, there may be another around.”

“Why did you invite me?” Sean asked as he looked around the console room in undisguised awe.

“Because it is just possible that I was wrong when I said that Garrick and I were the first aliens to set foot in the Azores. If my suspicions are right... Well, bringing you along is the least I can do.”

“What makes you think you were wrong?” Sean asked.

“Ion particles,” Garrick said. “I felt it, too – when we were near the lake bed.”

“Ion particles are harmless,” Christo was quick to point out. “They don’t affect the water or the plant or animal life in the lake. No human technology would even detect the presence.”

“But you two could both sense these particles just like I was talking about the fish sensing seismic events?”

“Ion particles are left behind when any kind of matter transmission takes place. It is a certainty that advanced technology has been used. Humans haven’t even come close to harnessing ion fields in that way, yet.”

“So it has to be aliens?” Sean was excited. Christo didn’t try to curb him. He was intrigued, himself. What race had buried itself at the bottom of a caldera lake on an island a thousand miles from the nearest continent?

And why?

The only way to find out was to go back to the Lake of Fire by TARDIS.

That was a remarkable enough experience for Sean and for Garrick as they both stood at the door with a force field holding back the water.

It was night, of course. Their dive had been in bright daylight. The water life caught in a strong light from the TARDIS was behaving in subtly different ways.

But the fish weren’t the reason they were there. Christo was watching the monitor that was not only picking up the trace of ion particles but was giving him a direction to follow.

“I have to close the door, now,” he said. “We’re going down.”

“Down?” Sean asked. “Down where?”

“There is a large space beneath the floor of the caldera. It was probably formed some time after the original volcano collapsed into itself some fifteen thousand years ago, but if I’m right there has been some interference to prevent nature taking its natural course.”

The TARDIS moved only for a brief time before it rematerialized in a darker place even than the caldera floor at night. Natural light had never once penetrated this cavern in its whole existence.

Christo switched on external lights that illuminated a place that had not even seen artificial light for a very long time.

“There’s no breathable air out there,” Christo said. “Very high levels of sulphur dioxide, a lot of nitrous oxide and all kinds of carcinogenics. We all need protective suits and oxygen tanks to go out there.”

“I'll wear a copper helmet and diving dress if it means I can see that with my own two eyes,” Sean declared.

The Gallifreyan idea of a protective suit and helmet was much less cumbersome than the prototype diving wear Sean referred to. All three explorers were able to walk normally when they stepped out of the TARDIS's protective field.

Sean immediately went to the alien computer array that was at least four times the size of the TARDIS console. The whole thing was covered in a film of yellow dust that Christo confirmed as sulphur with one sweep of the sonic screwdriver.

“The last major eruption here was 1563,” he said. “I think that was when this place was abandoned by the extra-terrestrials who came here.”

“They didn’t die here?” Garrick asked.

“No,” Christo answered. “This place is hermetically sealed with no air, only a load of nasty gasses that even bacteria can’t live in. There would be bodies here, probably desiccated, mummified rather than skeletons, but definitely still here. We know from the ion traces that they had some kind of transmat system.”

The natural walls of the cavern were about five hundred metres around. Garrick walked it and confirmed that there was no exit tunnel of any sort. Transmat was the only way in or out.

Christo, meanwhile was attempting to power up the alien computer. He wanted to know exactly who had set up such an elaborate system inside a volcano on a remote island.

“Traditionally the inside of a volcano is the lair of the supervillain,” Sean said, not exactly helpfully.

“You mean, like Blofeld, Doctor Evil....” Christo laughed. “Yes, I’m familiar with the film trope. I can’t quite see what evil plot could have been formulated down here. If I can just... There is no good reason why I can’t get this computer to work. Its principle isn’t much different to the TARDIS and it has its own built in power source. I think it just....”

Sean and Garrick were both a little stunned when Christo suddenly hit the computer array with his fist and it just as suddenly powered up.

“Just a bit temperamental,” he said as a few key presses lit up a huge virtual screen. Christo's fingers flew across a keyboard with unfamiliar symbols on it and the same unknown language filled the screen along with schematics and images that were recognisable as São Miguel island and the rest of the Azores island group.

There were other images, a whole documentary record of the still unknown people's mission here on this island, indeed, on planet Earth itself.

“I think we understand, now,” Christo said, eventually. He turned off the screen and powered down the alien computer. The only difference from when they arrived was some disturbed sulphur dust and Christo’s fingerprints on the keyboard.

They returned to the TARDIS and took off the protective suits. Christo programmed the TARDIS's return to the Ponta Delgada marina before they talked about what they had learnt.

“This time you win,” Christo told Sean. “There really were aliens here, and they actually were committing the biggest alien conspiracy act of all time – abducting humans.”

They had all seen it in the mission logs. The aliens in their lair beneath Lagoa do Fogo generated enough power to open an interstitial portal in the ocean just beyond the islands.

“They netted boats attempting to cross the ocean... Those north African explorers from the late stone age that the Portuguese government didn’t believe in. Some of them may have gone on to the Americas, but some of them went somewhere else.”

“But... Not for sinister reasons,” Garrick pointed out. “We saw it... The other world beyond the interstitial portal... It was beautiful. The humans in their boats reached a place where they could prosper... Just what they set out to find... A New World, literally.”

“Technically, an old world that had been destroyed by an asteroid strike and renewed after a million year ice age and a slow, gradual thaw,” Christo pointed out. “The original population had evacuated before the cataclysm and long since settled on new worlds of their own, but their scientists set out to find people elsewhere who could inhabit the renewed world.”

“It sounds all right when you put it that way,” Sean said. “But its still alien abduction of Humans.”

“Yes, it is,” Christo admitted. “And primitive humans at that, with no awareness of what was happening to them. It is against at least ten intergalactic laws that I can think of right away and probably a few more I could look up. I ought to report this to my own people, at least. They don’t approve of interfering with the natural progress of primitive races.”

“Ought to?” Garrick and Sean both queried his choice of words.

“I think we all agree there was no malicious intent with these abductions. And it all happened a long time ago. Those original abductees are long dead and their descendants are living on that New World they were taken to. Any action now would interfere with THEIR destinies.”

“I get that, I think,” Sean admitted. “So you think we should just leave it alone?”

“The cavern is unlikely to be discovered by any Human exploration of the caldera,” Christo considered. “In the course of time, volcanic activity may well destroy it all anyway.”

The TARDIS had rematerialised in the marina. They all felt the need to breathe fresh air after the sulphurous cavern. There was a late opening cafe where they ordered coffee and sat looking out over the sea wall to where the riding lights of the RSV Wayfarer were visible.

“So...” Sean began, slowly, as he thought about what he had witnessed. “We brought no evidence of what we found. Even if we had, who would believe it? Did we get anything out of that little adventure?”

“We all learnt something we didn’t know before. Sean, you got to see with your own eyes that sometimes your alien conspiracy theories might have something in them, though not quite in the way either of us expected. Garrick, meanwhile, learnt that the Phoenician sailors really did get this far from their home soil and much further, which means he knows more than the Portuguese government about that subject. I learnt not to make statements like ‘no aliens came to the Azores before me and my brother' without being very certain of my facts. A little nugget of precious wisdom for each of us.”

Sean considered that and agreed.

“So... What about the story that there is a sunken pyramid lying just off these islands?” he asked.

“Internet hysteria and really bad Photoshopping,” Christo answered. “Don’t waste your time on THAT one.”