Professor Garcia truly seemed to be lecturing at that moment, and Xia De thought he should perhaps turn up the gas lamp a little to make the place more like a classroom:
"Regarding the rules of the time key, this was mentioned in your 'Fundamentals of Time Travel Theory' course. Also, don't worry about any troubles caused by time travel; our world is not as fragile as you imagine, and mortals are not as powerful as they imagine themselves to be. In a world where thought can influence matter, the world itself is the most powerful. Now, please take the key from the basin."
He resolved all of Xia De's questions with a single statement; probably every student undergoing time travel for the first time would have similar questions.
"Basin?"
Xia De looked at the glowing basin, squatted down, and put his hand into the water, which was somehow warm, and then truly took out a key.
It was a small wooden key, not even as big as Xia De's thumb. The flat key had an ordinary shape, with teeth on one side and a very smooth surface on the other. The wood grain on the key's surface was exceptionally clear, and upon closer inspection, a line of characters smaller than a grain of rice was found carved into it.
Although he had learned his lesson from the previous incident with the darkness box, this time it was clearly safe. Therefore, Xia De once again displayed his translation talent and deciphered it as:
"The World Tree protects you in time."
"World Tree?"
Xia De was surprised, but he didn't show too much emotion on his face.
"The Academy has various ways of transmitting relics, and Poet manuscripts are the most basic. The method currently used, though expensive, is safer and can transmit objects of a higher grade."
Professor Garcia still sounded like he was lecturing:
"The time key is graded from Poet Grade (Level 5) to Unknowable Grade (Level 0), and they come from the Old God, Father of Infinite Trees. Since this is only for course instruction, the time key provided this time is Poet Grade."
The Professor did not use the term "Old God" but rather the vague "God of the Past," which Xia De noted.
"Do you know anything about this God?"
The pointed-eared Professor asked.
"Only the name."
"The Father of Infinite Trees is a very special deity, special in that He Himself is also the World Tree."
If Professor Garcia had said this before Xia De deciphered the inscription on the key, Xia De's surprise might have been more genuine.
"You don't need to know about the World Tree for now. As for using the key, just point it at any lock, turn it, and push the door open, and you can go to a past point in time. Each key, before being opened, can reveal the corresponding time. The trick is to place the key under your pillow before sleeping; your dream will display the information left by the Father of Infinite Trees in the key. We use the era corresponding to the information to search for major events involving the Old God, and thus determine the key's grade."
"So, which period of the fifth epoch does this one correspond to?"
Xia De's fingers traced the wood grain on the key's surface.
The chaotic fourth epoch was too dangerous, and keys from the first three epochs were strictly forbidden for Ring術士 below 9th Ring, so this key could only be from the fifth epoch.
"Autumn of 1068, fifth epoch. The time point corresponding to each key must be related to an Old God. Therefore, the History Academy is proficient in the blasphemy element, because only the History Academy has the opportunity to safely obtain the silver blasphemy element without directly contacting existing evil gods."
Xia De did not think time travel was safe at all.
"We are Time Travelers, investigators. When entering the past, you cannot carry any items with extraordinary power; even if you try to, they will fall before you step through the opened 'door'."
Professor Garcia looked at Xia De, who quickly shook his head, indicating he had nothing now. Both the vampire ring and the dice of fate were in his study.
"When entering a past time point, there will be a large amount of white mist in our vision. 'The other me' will also provide hints about the time point and event information obtained from the relic key of the fallen God.
The white mist will not dissipate throughout the investigation. The investigator can only move to locations without white mist to witness what is happening. During this time, as long as you do not actively interact with the past, no one will notice you. We are investigators, witnessing and recording past events, and bringing these events back to supplement the missing history before the epoch."
"Are you saying we're actually going to watch a realistic movie... an opera?"
Xia De gave an example.
"A very good analogy."
A smile finally appeared on Professor Garcia's face. Although the pointed-eared Professor seemed strict, he was a very nice person:
"In very rare cases, the fallen Father of Infinite Trees may give you some tasks, but the probability is negligible... So, Mr. Hamilton, let's start now."
"Now?"
Xia De swallowed, looking at the bedroom door. Mia was probably tired, so the sound of her claws scratching the door hadn't been heard for a long time.
"Do you have anything else to prepare? Oh, don't worry, each opened period of time will allow you to stay for a maximum of 3 hours. And when you return to the correct time, you will only appear 3 seconds after you disappeared."
"I mean... isn't it too hasty, something like this..."
Xia De thought the instructor would provide some systematic training, but he didn't expect such a simple introduction.
"Ring術士 must rely on themselves, and of course, on 'the other me,' but not on others. You don't need to take notes with paper and pen; any substance you bring into the past will return to its original state when you return. Even if you truly have the ability to interfere with the past, it will only be a tiny ripple in the river of time. Do not underestimate time and the world."
"Alright then, Professor Garcia."
He stood up and went to the bedroom door, letting the light from the brass-colored gas lamp on the side wall fall on his head and shoulders.
The small key was aimed at the keyhole; unexpectedly, it fit perfectly, but the two were clearly mismatched.
"Remember, when turning it, you must recite the incantation, it can be in any language — May the World Tree protect me in time.
See you in three seconds, Mr. Hamilton. Please relax; the Academy has specifically investigated, and nothing dangerous happened in 1068 of the fifth epoch. This is very safe. Please cherish your first journey through time; it will be a memorable and interesting journey."
"Okay, see you in three seconds, Professor Garcia."
Xia De, feeling anxious, gently turned the wooden key in his hand and murmured:
"May the World Tree protect me in time."
There was a click, but his bedroom door lock clearly couldn't make such a sound.
Xia De took a deep breath and finally pulled open the door.
But behind the door was not the tired orange cat Mia and the bedroom; silky white mist slowly wriggled behind the doorframe. Behind the door was a misty portal filled with hazy white fog.
He swallowed, heard Professor Garcia's encouragement again, and, thinking of the cat, bravely walked in.