Chrístõ looked across the TARDIS console at his unexpected passenger. Riley Davenport was meant to remain on Beta Delta with Cal as his mentor and guide to a new life on a new Human world. The idea might work, eventually, but Riley wasn't yet ready to be a Beta Deltan. Cal did his best to help him, but professed himself baffled.

Chrístõ thought he DID understand.

“He's an explorer and adventurer. I've offered him planet Suburbia. For the same reasons I had to get away he can’t settle, yet."

The solution was equally obvious. Riley Davenport, former explorer of Earth's mysterious places would become his fellow traveller to the universe's mysterious places.

"There is a civilisation actually living on a flat world," he said. "Nobody is sure quite how it happened, but the place has gravity and atmosphere and spins like a plate creating seasons."

"I once saw an Arabian sculpture of a flat Earth supported by four elephants which were themselves standing upon a leviathan," Riley commented.

"No elephants," Chrístõ assured him. "But remind me to show you a space whale some time. Fantastic creatures and as close to a Leviathan as you're ever likely to see."

He reached to set the coordinates for the flat planet when the proximity alarm sounded followed by a peculiarly penetrating sound that made Riley clap his hands to his ears.

The sound stopped just as abruptly leaving a silence that made ears pop. As the two travellers looked around in confusion a figure began to solidify in front of them. It was tall, white-haired and white-bearded man dressed in a flowing robe. He was still slightly transparent when he pointed and beckoned to Chrístõ. He stepped forward and bowed his head respectfully.

"What do the Guardians of Eternity want of me?" he asked out loud. The answer came in a telepathic burst that felt like a fire brand thrust into his brain.

"I understand, sir," he replied. "I will do your bidding."

He bowed again and the figure bowed in return before fading slowly away.

"Was that ....." Riley stammered. "I mean.... was that GOD?"

"Not exactly," Chrístõ answered. "It was a Guardian of Eternity. They're.... mysterious immortals I suppose you could say. Even my people don’t know much about then. What we do know is that a mission from one of them is to be carried out without question."

"A mission?"

Chrístõ turned and looked at his TARDIS console. Seven gold spheres about the size of tennis balls were arranged in a triangle much like the balls set up for a snooker game or an exotic selection of wrapped chocolates. He touched one of them gently and felt the power within them.

"We have to take these Nodes of Eternity and place them in seven places in order to ensure that the inhabitants of a Class M planet develop culturally at the optimum time in their emotional development."

"Is that something you do? Guide the development of civilisations?"

"We don't... the Time Lords. We stopped doing it eons ago when the civilisations got too powerful for their own good. But the Guardians do - and they chose me to lend them a hand because of my particular affinity with this particular planet."

"Oh!" Riley exclaimed. "You mean Earth, don't you?"

"Yes. I hope you don't mind waiting a bit longer for a genuinely alien planet. This ought to be right up your street, though - visiting ancient historical places you could only see as ruins in your time."

Chrístõ moved around the console and set the co-ordinates for the first of the seven locations. Riley watched him quietly for several minutes, but he had some disturbing thoughts that he couldn't hold in for much longer than that.

"Look here, Chrístõ," he said when he finally decided to let it all out. "I'm not sure I like the idea of aliens interfering with the development of human civilisation. I mean... I've heard the theories about the Sphinx being too sophisticated for the ancient Egyptians to have built without some more advanced civilisation guiding them, and how the Nazca people in Peru created huge images on the ground that are only visible from the air... thousands of years before flight was possible. Was that these Guardians interfering with humans? "

"As it happens, no," Chrístõ answered. “The Sphinx theory is mistaken. There’s nothing sinister about it, at all. And it isn’t true that the Nazca lines can only be seen from the air. They are visible from the surrounding hills. The Nazca people were amazingly good at geometry, that’s all.”

“So aliens haven’t interfered with Earth in that way?”

Chrístõ thought it might not be a good idea to mention that a group of Prydonian post-graduates had once taken a trip to ancient Greece and posed as the Gods of Olympus, leaving behind some unlikely legends and a written language like nothing else on the planet at the time. The prank was severely frowned upon by the High Council and all of those responsible had their time travel privileges withdrawn, but Riley was not in a mood to hear that.

They landed surprisingly quickly. The Guardians seemed to have provided express co-ordinates. There was just time to change into suitable clothing for the time and place. These were not unusual for Chrístõ, being robes not unlike the everyday clothing of Gallifrey with the addition of leather sandals and turquoise blue turbans.

“There are two ways of getting to see everything in a new place,” Chrístõ explained as they walked along a camel track between fertile and watered fields. They were heading to a walled city rising up incongruously in the flat landscape. “You can either be a servant who moves quietly and anonymously and is rarely questioned, or you can be a member of the wealthy class who is noticed by everyone but NEVER questioned about his movements.”

“We’re coming as wealthy men?” Riley noted. His robes were heavily embroidered with gold and crimson threads and there were gold ornaments on his cloak. Chrístõ looked even more spectacular, not just because of the richness of his clothing, but the lordly bearing he had when he walked. Riley couldn’t imagine his companion trying to disguise himself as a lowly servant with eyes averted from his betters.

“We are ambassadors from Sumer,” Chrístõ replied. “Come with cordial greetings to king Sennacherib of Assyria at his palace in the city of Nineveh.” He waved a jewelled hand towards the walled city ahead of them on the desert road. Those walls were at least fifty feet high with watch towers rising even higher yet. Towers and pinnacles of the finer buildings within were visible above these defensives. This was a city of great importance.

“King Sennacherib?” Riley dug into the long buried memories of a classical education. “Six or seventh century BC?”

“The very man.”

“Why?”

“So that we can view his great Hanging Garden. It is one of the seven places where we need to conceal one of the nodes.”

“You mean… the Hanging Garden of Babylon… one of the Seven Wonders of the Ancient World. We’re going to each of the Seven Wonders with these nodes?”

“I told you it was right up your street.”

“Yes… but I think you’ve got the wrong address. The Hanging Gardens of Babylon were in Babylon. They were built around 600BC by King Nebuchadnezzar II for his wife, Queen Amytis who was from Median and missed its mountains when she came to live on the flat Babylonian plains.“

“That’s one theory. But the TRUE one is that they were built by the Assyrian king Sennacherib in his capital city on the River Tigris - broadly speaking, within the territory known as Babylonia. The bit about indulging his wife is true, but Nineveh is the place with the legendary garden."

"You really think so?" Riley was unconvinced until they had passed through the great gates in the high wall of the city. Then as they were escorted through the sun-baked streets his eye was drawn to one of two splendid features of the city. The first was a glorious palace with gilded pinnacles at the top of magnificent white walls. To the east side of the palace, where it would catch the early morning rays, was an artificial mountain created by tier after tier of wide steps held up by arched walls. Palm trees and shrubs grew on each step, watered by a cascade of crystal clear water that must have been transported to the top by technology he had never attributed to the people of this time.

"Nothing like the pictures I've seen of the Gardens," Riley admitted. "But then most of the images are fanciful. None of them are contemporaneous. The garden IS the only one of the seven wonders that has no trace left to modern archaeology."

"No wonder, since they are looking in the wrong place."

"In which case…." Riley added. "If I could prove that the gardens were in Nineveh... it would be as important as Carter's discovery of...." Then his enthusiasm fell into a sudden chasm of despair. "I can't do any of that. I'm dead. My career in archaeology is over."

"You're alive and kicking and you're seeing something amazing. Be glad of that."

It was the core of Riley's troubles, of course. The fact that his life as he had lived it on Earth in the early twentieth century was over had hit him hard. Small wonder he found life on Beta Delta impossible.

"I am glad to be alive," Riley assured the man who had saved his life. "I’m just not sure what I’m supposed to do with the future you gave me."

"Then don’t worry about it for now. Enjoy the past in its whole glory."

Of course, their escort of royal guards understood nothing of their conversation in English. One of them glanced at them suspiciously, though.

"I have been to Sumeria," he said. "I do not recognise your tongue as being of that place."

"We were speaking in High Sumer, not the dialect of the peasants," Chrístõ answered him quickly. "Do your Ninehvan aristocracy speak in the same common tongue as the ordinary kind?"

"King Sennacherib is a man of great learning who knows the tongues of many other kings and noblemen," the guard captain answered. "You need not doubt his royal blood."

"Indeed," Chrístõ answered in an imperious tone that silenced all possible questions or criticism.

The palace was as impressive inside as it was outside. The walls were faced with white limestone hewn from quarries far from the city and decorated with bas relief images glorifying the achievements - mostly military - of King Sennacherib. Every doorway was guarded by a pair of sacred bull sculptures, symbols of the king himself. Long before they reached the throne room they were left in no doubt about the greatness of the Ninevehn king.

"I've seen some of these in the British Museum, " Riley said about the reliefs that they passed. "Though in pieces, fragments, incomplete."

"Yes. I've seen them, too. They look better like this."

"These reliefs aren't about Sennacherib’s battles," Riley noted about one particular group of sculptures. "These look like a blueprint for a canal, and some sort of aqueduct. Look at those arches on the reliefs. I think they’re the same style as the garden elevation. I think they've brought the water for those cascades a very long way."

"That fits with the archaeological evidence of the early twenty-first century," Chrístõ replied. “When the possibility of this city as the true location as first explored.”

Riley was interested to hear about the archaeology that took place after his time, but the conversation had to end as they were announced to the King in his throne room.

This was where Chrístõ's training in diplomatic circles came in. Riley carefully followed his lead as they approached the throne dais, bowing and making obeisance to the man who sat there. He certainly looked like somebody who commanded obeisance. His robes of satin were embroidered with gold thread and he wore a magnificent headdress of gold and precious stones. His beard was full and his eyes bore testimony to the strength of character it needed to rule even a small kingdom in these often warring times.

"Your majesty, we bring a gift of gold and jewels from Sumer, in recognition of your greatness." Chrístõ waved and a servant brought the casket he had personally carried as far as the city gates.

The casket was opened and Sennacherib looked upon the assortment of gold and diamonds, both products of the family mines on Gallifrey, and was satisfied. The casket was taken to his treasure room to add to his wealth. The two ambassadors were invited to sit on silk cushions and drink wine with the king.

That was mission accomplished. They were accepted in the court of King Sennacherib. Access to the garden would not be difficult, now.

The problem was actually getting the opportunity to go to the gardens. The king was in no hurry to leave the throne room. Various entertainments including music and dancing girls in very minimal costumes took place within the same room. Wine and sweetmeats gave way to a full banquet of food and drink attended by three elaborately dressed women who might have been Sennacherib's wives and countless courtiers and attendants. The music continued, making serious conversations difficult. The only discussion of any significance that took place was about how little the two Sumer ambassadors ate. Chrístõ and Riley both chose carefully and consumed only small portions of the food, aware that they were used to very different expectations of kitchen hygeine and freshness of meat and that they had none of the acquired immunity to bacteria that the people of the time would have.

"In a time of feast or famine people ate well when they could," Chrístõ pointed out later when they were conducted to quiet sleeping chambers to sleep.

"It doesn't make the famine any easier to bear. Humans have no efficient way of storing fat long term in the way some animals have," Riley noted before moving on to another matter entirely. "Those dancing girls, did you see them?"

"Not being blind, I did " Chrístõ answered.

"The arrangement of fabric and straps to hold...." Riley’s hands described what he didn't have words for.

"You aren't interested in women," Chrístõ reminded him with a gentle laugh.

"I'm not blind, either, " he countered. "but I thought the... brassiere... was only a recent invention in my own tine."

"A reinvention, at least," Chrístõ assured him. “It will stay in vogue for a lot longer the second time around. And that is enough on that subject for two unmarried men. How tired do you feel? I ask because I rather think we might take a night time visit to the garden. Even if we are granted an official tour tomorrow we will be accompanied and I won’t be able to complete my task."

"Will we be allowed to wander unaccompanied? Won’t the palace be guarded?"

Chrístõ handed his companion a medallion of dull grey metal with a swirling symbol etched in it. It hung on a thin chain.

"It’s a perception filter, used on my world in places like libraries and the public gallery of the High Council chamber when spectators are expected to be discreet. It’s not an invisibility shield as such, but it allows us to be unnoticed by anyone not expecting us to be there. Sometimes it doesn’t work on guards - if they are on high alert and ARE expecting intruders, but this palace is peaceful enough."

Riley put the medallion around his neck and didn't feel any different. Chrístõ did the same.

"I can still see you."

"Because you know I’m there. Come on. We'll stroll down the corridor and prove to you that we're unnoticeable."

Riley still wasn’t completely convinced, but he followed Chrístõ out into the torchlit passageway that ended in a long staircase. They didn’t actually see any guards until they were near the main door. Riley hesitated when he saw them with long, sharp javelins in their hands and sword at their waists. Chrístõ winked at him and stepped forwards. He deliberately walked up to each guard and waved his hand in front of the unflinching man’s face. When he had thoroughly proved that his perception filter worked he winked at Riley and quietly moved away.

“If we open the door they WILL notice us. We’ll find a side door. There will be one for servants to come and go.”

Such a door was found, unguarded, not very far away. They slipped outside and found themselves on a terrace guarded by reclining bull sculptures. The terrace gave way to a well-tended and clearly very well watered lawn. That in turn brought them to an artificial lake at the base of the equally artificial mountain that formed the great, near mythological, Hanging Garden.

It was a moonlit night and the magnificent structure could be seen in all its intended glory except that the natural colour was washed out by the lack of sunshine. Despite having a duty to perform Chrístõ was as awed as Riley to see it and both stood for a moment appreciating how remarkable it was to be able to stand there at all.

"That’s how the water is raised," Riley said in an excited whisper. "Sennacherib has a form of Archimedes Screw system."

"Archimedes won't even be born for another couple of centuries," Chrístõ pointed out. "It looks like the brassiere isn't the only thing that will be reinvented at a later date. I don’t think he can be accused of plagiarism, though. I doubt he ever travelled beyond Greece, and even if he had, I think this would be gone by his time."

They walked up a stone stairway between two of the screws that drew the water uphill against gravity and then let it fall back down in cascades that watered the trees and fragrant shrubs. At the top, again they felt they wanted to stand for a while, just marvelling at the fact that they were there.

"There is nothing in my time to suggest that this ever existed," Riley said as he looked across the moonlit plains of ancient Babylonia from that great vantage point.

"It was lost long before then - before any reliable account of it was written down. The saddest thing is that, a hundred years after your time, Nineveh’s ruins were on the edge of a new city, called Mosul, that was in the midst of a war. The treasures of the past were pulverised by bombs and mortars, and archaeologists couldn’t get near it for fear of being caught up in the terror. Most of the evidence of the great city that hadn't been taken to the British museum before then was destroyed."

"So we really are lucky to see this."

"We are."

Chrístõ reached into a pocket beneath his robe and found the node he was meant to leave. He held it on the outstretched palm of his hand for a moment, watching it spin under some power of its own. He placed it on the ground and it span even faster, boring a hole into which it plunged. Chrístõ and Riley watched until the soil crumbled back over the hole. They guessed that it had buried itself deep enough that it would never be found by even the most determined archaeological dig.

"It will still be there when the site is a war zone? "

“Still there, yes, somewhere. But whether it will still be active... the Human race in the second half of your century makes so many leaps in technology... especially weapons.... I find it hard to believe anything is asserting any control over them."

"I'm still not sure aliens controlling humans is good," Riley pointed out.

"If it wasn't done, Sennacherib's children might be the ones developing mortar bombs and levelling the city," Chrístõ insisted. "Come on, let’s head back to the palace."

"Is there any hurry?" Riley asked. "We're here standing atop one of the Seven Wonders of the Ancient World. Can we enjoy it a little more? Would anyone care if we saw the sun come up?"

Chrístõ's first instinct was to get back to the palace quickly, but he fully understood Riley's desire to enjoy the Wonder for a little longer. They both sat down, facing towards the eastern horizon and looked at the stars.

“That’s the constellation of Sagittarius,” Chrístõ told his companion. “My homeworld is there. This is one of the best parts of Earth to see it clearly.”

“What’s your world like?” Riley asked.

“The northern part is rather like this, actually,” he admitted. “There’s a huge desert with distant mountains of the red-orange rock that the desert sand was scoured out of. The southern continent is more watered and fertile, but still a lot of vast, empty plains where it is possible to feel quite alone.”

“Do you miss it?”

“I miss my family, but the rest of the planet is easier to love from afar, away from the political wrangling and the petty rivalries that I always hated.”

“I… miss England. My England… in my time.”

“I know. But there’s nothing I can do about that. I can’t fit you back into the fabric of causality once the expedition went missing and you were all presumed dead.”

“I understand. It’s just hard, sometimes, to realise that everything I took for granted is gone.”

Chrístõ gave a sudden gasp. Something in what Riley said struck him deeply, as if he was the one faced with the terrible realisation that everything he knew was gone. It was a terrible feeling, and if he had ever underestimated Riley’s grief, he knew he never would again.

“I… am sorry,” he managed to stammer, and somehow, instead of trying to comfort and reassure Riley, his companion had to do the same for him.

“You don’t have to be sorry,” Riley told him. “I’m glad to be alive. I will never give you cause to regret saving me, or resent that you did. I just have to try to find out where my future lies. It might be on that planet you took me to, or somewhere else. I will know when I find it.”

“I’ll try to help you find it.”

“Thank you.”

The conversation died away and they sat in near silence as the night wore on and gradually the eastern sky began to lighten. The constellation of Sagittarius low in the southern sky was swallowed by the pale blue before the sun pushed its rays over the horizon and the desert lands of Babylonia blazed orange-red. They watched in awe as the daily miracle took place. The sun rose, spreading heat and light that in a few hours would be too hot and too bright.

“The servants will be waking, if not the king and his family,” Chrístõ said. “Time to get back, now.”

They walked down past those surprising screws pulling cool water uphill and slipped back into the palace. As they reached the entrance hall, though, where Chrístõ had proved how well the perception filter worked they became aware that there was something wrong. Despite the fact that they were still wearing the filters, they hid behind two of the largest bull sculptures and watched the dangerous turn of events unfold.

It was very bad news. A trade caravan from Nineveh had been attacked, somewhere near Sumer. The traders were killed and their goods stolen. Sumerian bandits were believed to be responsible.

“Fetch the ambassadors from that cursed city,” demanded King Sennacherib, who seemed as angry about being roused early from his bed as about this attack on his subjects. “They shall be held as hostages. Send word that they will die slowly and painfully if any other citizen of Nineveh is attacked by Sumerian murderers.”

“Time to go,” Chrístõ whispered. “Before they find out we’re missing. I don’t fancy the chances of the perception filters working once they start looking for us.”

Riley didn’t offer any argument. They moved quickly and quietly through the still quiet city. The hue and cry had not yet been raised. They made it to the great gate and out into the desert without being waylaid and hurried to the place where the TARDIS had been left, disguised as a large erratic rock made of the same minerals as the sand around it.

“That was close,” Chrístõ said as he set the TARDIS on its way to the next destination.

“I hope we’re not going to run into trouble like that every time,” Riley commented.

“Unfortunately, in my experience that’s exactly the sort of trouble that happens when I travel,” Chrístõ admitted. “I find calling it ‘adventure’, not ‘trouble’ actually helps.”

“Then here’s to the next adventure,” Riley conceded.