No matter the significance of a discovery or invention, it is inevitable for humans to get used to its presence in the course of a surprisingly short time and begin considering it a part of their mundane lives. Things once deemed impossible end up being taken for granted, with only a brief period of amazement and a sense of ongoing revolution dividing two eras of collectively perceived banality. Among all the great technological innovations in the history of man, such was also the case with time travel, or at least that of its components which allows for revisiting the past. In hindsight, it wasn't that difficult of a problem – but then everything seems easy to solve once someone finally succeeds.

Few categories of human activity remained unchanged after the breakthrough. It wasn't just data collection, criminology, and the study of history that found a new purpose and skyrocketed in popularity; it was even the less obvious fields like treasure hunting, tourism, or simply entertainment. It could be said that a new dimension was made accessible to man and if there’s one thing that he, being a part of nature, abhors, it certainly appears to be vacuum in the form of unexplored – and ungoverned – spaces.

Now, you might ask how the temporal continuum managed to survive the countless excursions that were vehemently claimed by some to pose a threat to both the past and the present. The concern itself was valid – after all, the consequences of killing one’s own grandfather were either grave or paradoxical; and even if going back in time had involved crossing the barriers between parallel universes unconnected by the laws of cause and effect, there was still the question of ethics and responsibility. As it turned out, the answer to the question of free will would not come packaged with time travel, nor would humanity discover whether the multiverse really exists.

The person that came the closest to getting everything right was Novikov; only one timeline exists – or, at the very least, remains accessible – and it is the laws of physics themselves that prevent anyone from changing the past in a paradox-inducing way. There is perhaps no other concept more central to a layman’s understanding of these very limits – as viewed within the framework of the now experimentally revised theory of time travel – than the butterfly effect, which reveals that even a small initial change in a chaotic system can affect the long-term evolution of its state. Fortunately for those who partake in excursions to the past, while the universe bears the characteristics of such a system, it is not as chaotic as once thought – there is some “wiggle room” that allows for new events to be caused retroactively, provided that the level of their influence on the bygone world is on par with that of random noise.

So what did Novikov and everyone else miss? It was widely assumed that the laws of physics would prevent logically impossible events from occurring only in response to the time traveler’s attempts at creating a paradox; the gun he had brought, for example, to kill his grandfather would jam every time he attempted to fire it. However, as we now know, the sheer act of sending an object back in time renders it incapable of changing the course of history; and so, it is almost impossible to arrive in the past with a working – or even repairable – firearm. The extent of this effect depends on the significance of the moment that was chosen to be revisited and its temporal distance – the further in time something took place, the more difficult it is to reach it. The window of opportunity is thus constantly shifting, which explains why it is possible for contemporary humans to discover new available exits even though they are in direct competition with the nigh infinitely numerous future time travelers. In light of this, the aspect that makes this technology practical for humanity at all is the increasingly more accurate ability to mathematically predict what state an item will be after it undergoes the transmission procedure without the need of sending it blindly first. Recovering all the physical material that was admitted to the past turned out not to be an issue as well; that is, as long as the exit node is placed in a way that allows for fundamental forces of appropriate strength to be carried over, which in most cases simply involves attaching a cord to the object or not inserting it fully.

The transformation process inherent to time travel manifests itself through a great variety of mechanisms and phenomena that depend on the set of initial conditions and the destination chosen, all of them resulting in physical changes being applied to some degree to the object revisiting the past in accordance with the principle of insignificance. However, only one such transition has so far been proven to be safe for biological matter, including humans; and so for all intents and purposes, going back in time has become synonymous with the process of miniaturization.

Thanks to the Herodotus programme of the European Union, our university has recently become capable of facilitating excursions to the past without having to rely on third-party partners. It is therefore no longer necessary for history students to travel each semester to the capital to pass the practical components of their education programme. The schedule, however, remains unaffected.

End quote.

Those were the words of the Faculty of History’s dean, heard by all the freshmen whom she managed to gather inside the big lecture hall right before their first finals. For most of them, it wasn’t anything particularly new. Having been widely commercialized and made accessible to everyday people – similarly to air commuting in the previous century – time travel had become an activity with which young adults in developed countries generally had at least a bit of personal experience. That wasn’t the case with Michael, though; he had never really had a chance to see the world as it had been, and that made him feel left out and inadequately prepared for what was soon to come.

As the meeting concluded and the students began to get up from their seats and leave the hall, Helena chatted Michael up.

"You must be excited," she said. "You'll finally have a chance to see for yourself what it's like to go back." 

"Of course I am! Though it's a bit jarring. Especially the part that has us getting small."

"Oh, don't you worry about it, it makes the whole thing even more fun; have you never fantasized about shrinking down and exploring the world from an ant's point of view?"

"I sure have. I think everyone has at some point. It's just that nothing bad can really happen in your daydreams. Real life is messy and unpredictable."

"Nothing bad is going to happen during our trip, either. You heard the dean; it's physically impossible not to be safe! We'll be like ghosts."

"Was that really what the dean said…?" he thought, holding himself back from saying it out loud. He found it irresponsible for people to treat time travel so casually and make light of all the dangers. Sure, it was much safer than it had been back when the first travelers painstakingly paved the road for future generations, but visiting previous centuries wasn't a mere weekend trip. He did not, however, want to argue with Helena; it's not worthwhile to argue with people you have a romantic interest in. Perhaps he was unnecessarily gloomy. He decided not to spoil the occasion.

"I guess," he replied. "I mean, we're going together. We'll have each other to lean on. Right?"

"Definitely! You can lean on me as much as you'd like. I'll make sure nothing bad happens to you."

Both Helena and Michael studied ancient history, and, being in the same year, they mostly attended the same classes. They dreamed of becoming archaeologists, but that was now an occupation for the elite few. With time travel breathing fresh air into the lungs of a once dying field, its sudden revival and rise in popularity caused the admission requirements to skyrocket along with the level of difficulty of its courses. They did not let those challenges discourage them and besides that, they did genuinely enjoy their studies. For one reason or another, not long after Michael transferred from abroad to Helena’s home university, something sparked between them both in terms of shared interests and romantic feelings about each other that crystallized within their friendship as occasional flirting, though never anything serious. And so, while they weren’t the only students thrilled to hear that the university managed to secure a couple of timespots for them, all in Roman-era Egypt, it was unlikely that anyone else considered the romantic charm of the excursion.

A little over two weeks after learning about their school’s acquisition of its own transtemporal equipment, the students of ancient history – or at least those among them who managed to pass their finals – found themselves in the last stage of preparations for their trip to the past. Having been divided beforehand into groups of six people, including the guide, they gathered in a classroom adjacent to the portal room for a quick recap of their safety seminars. It was also at this point that their exact destinations were revealed, all of them being great settlements along the Nile from the 1st century BC Ptolemaic era: Memphis, the Old Kingdom's declining capital; the Giza pyramid complex; the Library of Alexandria; and, finally, the Ptolemaic Royal Palace. 

Dressed up in university-issued, significance-neutral clothing and ready to put their training into practice, Helena, Michael, and the other three students from their group were instructed to proceed to the chamber housing the machinery that would take them to the age of Caesar and Cleopatra. As they entered the room, they got somewhat taken aback by how unimposing the machinery appeared. Being about the size of an MRI scanner, it wasn’t one of those industrial monsters that some of them had the opportunity to use when booking a commercial tour. Still, it would do its job just fine; it was fully capable of keeping a strong and stable connection for a group this small and its frame was big enough to fit even the tallest students.

They weren’t the first student group to leave for the Nile basin; the equipment had by no means been idling that day. By the time they entered the room, it was already running – under the supervision of a technician, that is, who was there to make sure that things were progressing smoothly, and so had just finished establishing their connection for them. Michael glanced at the square-shaped portal, the border between the present and the past. He obviously had had some idea about how it would look – it was nigh impossible to miss all the publicly available footage after all – but he had never seen one in real life before. It was pitch black – just as he had expected – and resembled a tightly stretched membrane.

“Hey, Michael, take this,” Helena urged him. “We are forming a rope team.”

Michael grabbed the clip hook and attached it to his suit, his hands stiff and cold from nervousness. It did not help that the portal room was located in the basement and that the outfits chosen for this excursion were understandably simple and thin; everyone was anxious to leave for the warmth of the desert sands. The rope team’s vanguard was formed by the guide, who was then followed by Helena; she figured the trip would be more comfortable for Michael if he had her in front of him to lead the way. With time being of the essence in more than one way, the settings underwent a double-check and a signal was given to commence the excursion.

One by one, each member of the group disappeared into the weightless, black veil – as if it wasn’t even there. The guide entered the portal first, collectedly and confidently; Helena followed, with her arm stretched towards Michael. It was an invitation he dared not decline. He grabbed her hand and marched forward with a quickened step.

It felt like running into a wall – except it was neither painful, nor futile. In one stupefying instant, Michael emerged into a wholly different reality; an instant so abrupt and devoid of any fanfare that it made him wonder whether he had just woken up from a dream in which he was a history student in Central Europe. The blinding light of the zenithal, desert sun touched his hair with warmth he hadn't felt in many summers and made its presence known by giving each traveler a very short shadow. He could see Helena smiling at him, but before responding with a smile of his own, he needed to find his bearings; and so he briefly looked around and then gazed into the distance.

The group seemed to have exited onto an elevated field of stone placed high above a busy market square. White, ornate towers surrounded their observatory while the crowns of palm trees set in motion by the wind seemed to wave at them as they danced around by their eye level. The streets below were teeming with people going about their lives and making all sorts of noises, many of them being quite obviously speech, but their language was beyond the students’ expertise. To Michael, It all seemed fake; he had only known this world from movies and books, which now made reality itself look like a mere stage. One thing, however, was genuine to him beyond all doubt: the side effects of passing through the portal. He didn't know how tall he was exactly, but it couldn't have been more than a few centimeters. The fine Saharan sand that accumulated on the roof he discovered the group was standing on seemed more like gravel to him, and the supposed abyss below could not have in fact been more than a couple of stories deep, as evidenced by the locals who were walking by the neighboring buildings.

Wasting no time, the guide began explaining to the students the circumstances in which they had found themselves; alas, Michael was in no shape to pay any attention to his words. The only thing he managed to notice after shaking off his initial confusion was that he hadn’t let go of Helena’s hand. Slightly embarrassed about being so blatant, he swiftly made appropriate amends.

“You okay?” she whispered to him.

“Uhh, yeah. I’m fine,” Michael responded, having trouble putting his emotions into only a handful of words. “Thank you.”

Just as Michael was starting to get used to the turn-of-the-era Memphis, the guide signaled that it was time to go back. The rope that linked each member of the group, seemingly unconnected and slacking on the floor, began to move and disappear inch-by-inch as some invisible force pulled it away from the visible realm through an imperceivable, vertical opening in spacetime; and it did not stop until the whole group was dragged back to the university’s portal room.

“Everyone still in one piece?” the technician asked when the past was once again left to its own devices. “Good, this time you’ll be going to Giza.”

No less thrilled, though substantially better composed, Michael embarked on his second rodeo. Before him soon appeared the great Pyramids in their ancient glory, still smooth and white, their tops adorned with shining gold. It was a truly spectacular sight for the students to behold. The massive landmarks needed no introduction, but one was given by the guide anyway; and as Michael listened to him mention details he had already learned during his classes, his fingers brushed against Helena's hand, prompting their gazes to meet.

"You don’t need to let go," she whispered to him and gently grabbed his hand before returning to feast her eyes upon the ancient necropolis.

The Giza complex was an awe-inspiring destination, especially for those who had never seen it in person before, even in modern times, but no pyramid took the young historians' breaths away as much as the Library of Alexandria did. Vaults upon vaults of priceless ancient scrolls, many of them still unexamined by present-time scholars. The group emerged into a reading room of sorts – a place shrouded in pathos and solemnity that imposed a regime of silence and indisturbance, physically bringing everyone together. Standing on a dusty, shadow-clad shelf inside a place so dear to their hearts, their shoulders touching, their hands interlocked, Michael and Helena felt more intimate than ever. They both realized that the things they set in motion would culminate in something even greater before the end of the day.

"We've prepared something special for your final trip," the guide announced when the group returned to the portal room. "You're going to have an opportunity to see more than just a landscape."

"We're still going to the palace in Alexandria, right?" one of the students asked.

"Yes, but that's all I'm going to say for now. You'll find out more by yourselves in just a minute."

Passing through the portal one last time, at least in this semester, Michael felt the need to take in the entirety of the experience and savor the moment, just as one does when eating the final spoonful of a meal. With now familiar instantaneousness, the cold and mundane aura of the university basement made way for the grandiose warmth of a pharaonic residence; and more specifically, its great chamber, whose open, stone balcony overlooked the Mediterranean sea and offered a direct view of the famed lighthouse. Once again the group appeared in a place out of sight and mind; on the floor by an ornate pot, which seemed to them like a towering building. The leaves of the palm it was holding loomed high above the minuscule travelers, making Michael feel even smaller than before. 

“Don’t be alarmed by how big everything looks,” the guide preempted any comments or questions from the students, as if to answer Michael’s unvoiced worries. “That’s unavoidable, given the circumstances. We’re as close to the ancient people of Egypt as you can get; not just any people, too.”

The guide pointed to a colossal daybed standing somewhere far in the distance; not further than a couple of meters away in reality. Covered in a heap of richly decorated blankets, cloths, and fabrics, it was seemingly occupied by a person, whose back was turned away from the group of uninvited guests.

“Before you stands – well, lies – Queen Cleopatra VII, considered by some to be the last pharaoh of Egypt,” the guide announced.

Michael saw her clearly now; her strikingly black hair; her lightly gowned, sun-touched body and its delicate yet voluptuous figure; her smooth legs, bared by the subtropical heat and the privateness of her secluded dwelling. The intimacy of this encounter only added to her majesty. She remained, however, alien and unreachable, and so his mind wandered towards Helena.

“Not the only queen in this room right now,” Michael said to Helena before getting immediately overcome by regret over uttering something so cheesy.

Helena wasn't appalled by his sudden outburst of coquetry. Quite the contrary, she found it rather adorable. She let out a warm, hushed laugh and looked into his eyes.

"Oh, is that what you think?" she teased him while bringing her face ever closer to his.

"Yes," he whispered; and perhaps that would the moment they would forever remember as the time they shared their first kiss if it wasn't for one of their classmates loudly bringing everyone's attention to the safety rope, whose end, now loose, was dragging on the floor instead of joining up through the invisible, stationary portal with the part left behind in the present.