Time rewound to two hours ago, after Zhuang Yue ended her first call with her father and set out on her journey back to the dormitory from the office.
Leaving the steel building of the command center, the sky outside took on a charming lunar hue, occasionally adorned by passing clouds that added luster to the night sky.
However, these scenes were all projections from three-dimensional imagers displayed over the city, while Zhuang Yue was currently five hundred kilometers underground.
The airship she rode was piloted by a smart computer, which allowed her to admire the city's nightscape with ease.
This underground city was an expansion of a former subterranean city, but the tall tree-like structures had been dismantled. The newly built structures and surroundings resembled the style from the Common Era.
The cityscapes that resembled giant trees still existed, but they had been converted into museum cities and were scarcely inhabited anymore.
Now, Earth's population remained stable at about eight hundred million, allowing plenty of room for spacious living quarters.
Buildings were evenly distributed along the streets and alleys, similar in structure but differing in color, giving each home a unique style.
The streets on the ground weren't very wide; after all, people now traveled by airship, negating the need for space reserved for vehicles.
However, the rooftops of every building had several landing pads for airships to take off and land.
Of course, the most beautiful aspect was the city's greenery, interspersed among the buildings and bathed in light; amidst the backdrop of night, they radiated tranquility and harmony.
Every time Zhuang Yue witnessed these scenes, the anxiety accumulated from her day's work would dissipate entirely.
Cheng Ping's research team, which he currently led, was investigating a phenomenon that had garnered high-level attention from the Earth Province.
The research team's location wasn't far from Zhuang Yue's dormitory, so lately, before heading back to her residence, she would make a detour to Cheng Ping's place.
Just as Zhuang Yue expected, Cheng Ping hadn't rested either.
Although his temples were graying, he was spirited, showing no signs of old age.
Cheng Ping invited Zhuang Yue to sit on the sofa in his office, "Would you like some tea or coffee?"
Zhuang Yue replied, "Just a glass of water would do. Drinking anything stimulating at this hour would affect my sleep."
As Cheng Ping fetched water, he asked, "Teacher Logic should've come out of lightspeed today, right?"
"Yes," Zhuang Yue took the water and thanked him, "I just spoke to him."
Cheng Ping lit a cigarette and said, "I've been so busy lately that I forgot to send my regards to Teacher Logic."
"Your research should take priority; after all, it follows us," Zhuang Yue inquired further, "Any new findings?"
Cheng Ping took a deep drag on his cigarette, "You know, there really was a new discovery today."
He then commanded the room's smart computer, "Bring up the photos we took just today."
The lights in the office suddenly dimmed, and a colorful photo was projected onto one of the office walls.
This was what Cheng Ping had been studying recently. Three months ago, a flash of light suddenly appeared in space, faintly visible from the surface of Earth.
Viewed through a high-powered optical telescope, this colorful spectacle was revealed.
Its hues were in constant motion, reminiscent of the kind of fish in the ocean that emits colorful light to intimidate its opponents.
Initially thought to be a special phenomenon in the distant universe, it was a surprise to find during distance calculations that this colorful object was only about six thousand astronomical units away from Earth!
In the scale of space, this was alarmingly close.
Yet none of Earth's radars, even the most reliable gravitational radars, detected anything in that position.
Fortunately, this colorful spectacle lasted only little over two hours before disappearing without a trace.
While the Earth Province reported to the New Continent Star System, they hastily convened experts to discuss what this phenomenon might be.
But after lengthy discussions, no conclusion was reached. Just when everyone was relieved that this strange phenomenon came and disappeared inexplicably without affecting Earth,
It appeared again!
And again, at about six thousand astronomical units away, it disappeared after another two hours.
All of humanity immediately took the matter seriously, and research teams were established both on Earth and Blue Maiden Star.
At first, some guessed it might be a Rank One life-form, for according to the intelligence humanity had gathered, Rank One life-forms did not always take the form of planets.
But no matter what frequency of signal Earth sent out, there was never any substantive reply.
The probes that were dispatched disappeared without a trace as they approached the other party, and they did not transmit back any useful information.
The situation on both Earth and the Moon had become very tense, and the factories had already begun desperately producing star accelerators, ready to temporarily abandon Earth and the Moon at any moment.
It was at this time that Cheng Ping's research team made a new discovery. He pointed at the colorful image and said, "Look at that spot."
Zhuang Yue noticed a small black dot on that colorful image, "What's that?"
Cheng Ping had the smart computer zoom in, and Zhuang Yue looked for a long time before saying, "It looks like an escort ship!"
Cheng Ping pressed the cigarette butt into the ashtray and said, "That's right, we think so too.
"A spacecraft flew out from there! And it seems to be a human spacecraft!"
...
Back to the present, Logic saw his daughter didn't believe his words, and he didn't say much more.
After all, Zhuang Yue had just seen Cheng Ping; this was solid "evidence" from Earth!
After ending the call, Logic stroked his beard in thought, sure that one of the two Cheng Pings had to be fake.
If the Cheng Ping Zhuang Yue had seen just now was real, then who or what had he just been talking to?
And if the Cheng Ping he had seen was real, what was the Cheng Ping on Earth?
Moreover, there was also a third possibility: both Cheng Pings were real!
Thinking this, Logic felt his heart start to thump wildly, "The universe really is a paradise for adventurers; even I feel my old bones have grown younger."
Logic then asked Galaxy III, "Did you record my conversation with the guest just now?"
Galaxy III replied, "Yes." And then it began to play back the footage of Logic's conversation with Cheng Ping.
Logic nodded and said, "Good, please make sure to keep these recordings."
He then took out the storage device that Cheng Ping had given to him and waved it in front of the multifunctional camera, imitating Cheng Ping, "Read the data inside."
But Galaxy III said, "Sorry, this device has been encrypted. Please decrypt it first."
Logic put the storage device away and said, "Just as I thought." And then he went to the sleeping cabin to get some rest.
What hadn't Logic seen in his life? Nothing like this could affect his sleep.
And he patiently waited for five days, until navigation information came from Earth, and his spaceship was set to land on Earth.
Through the porthole, Logic finally saw a vast shadow in the dark space.
That was Earth, humanity's homeland, but now it was completely different from what Logic remembered.
The whole planet was hiding in the darkness, with not a hint of life to be seen.
While the spaceship descended, Logic murmured to himself, "Darkness is good, darkness is safe."
The landing site directed by Earth featured many steel structures, with lights on their exteriors, illuminating the barren icy plains of Earth's surface.
Logic muttered to himself again, "Looks quite cold."
The steel structure then opened, the spaceship flew in, and the ground began to descend rapidly as the iron walls above closed quickly, cutting off the cold from outside.
Logic didn't know how many meters they had descended; the descent began to slow, and the spaceship arrived in a brightly lit hall.
Outside, many people in thick cotton clothes were there to greet Logic.
Logic carefully adjusted his attire, and then he opened the door of the spaceship.
He saw a line of people waiting to shake hands with him at the bottom of the gangway.
So Logic took the opportunity to wave to everyone and counted: the first person he didn't know, the second was his daughter, Zhuang Yue, the third and fourth he didn't recognize either, the fifth was Cheng Ping!
"I..." Logic nearly let loose a curse.