My Invincible Defense: Traversing the Endless Worlds

Penny sniffed the air and asked in confusion, “Why can I hear a human heartbeat underground?”

“Master, may we investigate?” Olivia asked Finn.

“Let’s take a look. It might be a lead,” Finn replied, though he wasn’t certain either.

The off-road vehicle drove across the vast wasteland. Every so often, Penny jumped out and lay flat on the ground to listen.

Following her directions, they circled the area several times but still found nothing. Penny scratched her head in embarrassment.

“The heartbeat is too weak, and it keeps getting fainter. I can’t pinpoint its exact location. I only know the general direction and area.”

“What do we do now?” Olivia asked helplessly as she drove them in another circle. “Are we going to lose our last possible lead too?”

She took out a pair of binoculars and scanned the surroundings but saw nothing useful. The world was simply too vast, and humans too small.

Olivia gritted her teeth, her hands tightening around the steering wheel. Her eyes were full of frustration.

“Damn it! Are we really going to let the Wilderness Rhino caravan escape? I still haven’t made them pay in blood!”

Finn thought for a moment, then patted Penny on the shoulder.

“Do you know how trilateration works?”

Penny opened her mouth slightly and shook her head. “No. What’s trilateration? Can you eat it?”

“No, but you can use it to locate a stationary target.”

Finn took out a sheet of paper, a drawing compass, a ruler, and a pen. He had Olivia drive to several different points while Penny lay on the ground and estimated the direction and distance of the heartbeat from each position.

The principle behind trilateration was simple: use the known coordinates of three points and their respective distances from a target to calculate the target’s location.

Suppose the coordinates of the three known points were \((x_0,y_0)\), \((x_1,y_1)\), and \((x_2,y_2)\), while the unknown point \((x,y)\) lay at approximate distances \(d_0\), \(d_1\), and \(d_2\) from them.

Draw three circles using those distances as their radii, then apply the Pythagorean theorem. Under ideal conditions, the target would be located at the circles’ common point of intersection. Since Penny’s measurements were only estimates, however, Finn would have to calculate the location that best fit all the available data.

Although Finn hadn’t worked as an engineer in more than six hundred years, spending all that time cultivating and fighting instead, he still retained his fundamental engineering skills. That alone was enough to run circles around almost everyone in the wasteland.

After Penny supplied him with a series of measurements, Finn made no attempt to hide what he was doing from her or Olivia. He took out his phone and brought up a virtual keyboard and a three-dimensional projection screen.

Then, using the notoriously cumbersome assembly language, he wrote a trilateration program in thirty seconds. It compiled successfully on the first try, without a single error or warning.

Once he entered the data and established a topocentric coordinate system centered on their local position, he obtained the heartbeat’s probable location.

“Head for that banyan tree,” Finn said, pointing ahead.

Olivia drove over. After a quick glance at the disturbed ground beneath the tree, she cried out, “There! Someone’s been buried underground!”

Olivia praised him from the bottom of her heart. “Master, you’re amazing!”

Even Penny looked at him with newfound admiration. She had assumed Finn was merely blessed with superior genetics and hadn’t been entirely convinced of his abilities. Now she realized that his intelligence and knowledge left her own far behind.

Finn merely gave a modest smile, as if it were nothing worth mentioning.

These days, nearly all code was generated by AI, but Finn had never lost the ability to write assembly programs from scratch in a text editor(such as Notepad).

There was a practical reason for that. As a Celestial Sojourner, he might one day be thrown by a spacetime disturbance onto an uninhabited planet. If that happened, he had to be capable of building a fusion-drive spacecraft with his own hands.

Beyond every heaven lay another heaven, and beyond every great person stood someone greater.

At the Spacetime Destruction Bureau, there was a great scientist named Zhuge-Tyentse. Back in elementary school, whenever he wanted to write a computer program, he would pull out the hard drive and use a probe just 0.01 nanometers wide to manipulate every atom and electron on the storage medium. By altering the stored information directly, he programmed in raw binary machine code.

As for carving an entire operating system onto an optical disc with a needle? That was child’s play, hardly worth mentioning.

The soil beneath the banyan tree showed signs of having been disturbed, and freshly cut weeds had been laid over it as camouflage.

The three of them took out shovels and removed the soil layer by layer. Before long, a girl’s pale face emerged from beneath the loose earth.

Penny recoiled in fright. She was still young and couldn’t handle a scene that looked so much like digging up a corpse.

Finn didn’t stand back merely because he was the master. He joined Olivia in digging the girl out.

The girl’s face was white as paper, and her eyes were tightly shut. There were several bloody holes in her chest, arms, and thighs—obvious gunshot wounds.

Finn noticed that her skin was slightly darker. Her black hair had been woven into three braids.

She wore a gray leather jacket over a short animal-hide skirt. Two angular red-and-white clan markings had been painted across each cheek, and bracelets of polished, colorful stones encircled both wrists.

Olivia leaned close to the girl’s chest and listened for a moment.

“She’s still alive. Her heartbeat is very weak!” Olivia said. “Master, can we save her?”

Finn knew Olivia was kindhearted, so he took out a bottle of healing potion and handed it to her. He had little need for medicine himself anyway.

Olivia didn’t ask where the potion had come from. She simply poured it into the girl’s mouth.

She knew her master possessed extraordinary powers and many secrets. More importantly, she knew when to keep her mouth shut.

The girl’s gunshot wounds gradually closed, pushing the bullets out of her flesh.

She slowly opened her eyes. The instant she saw Finn and the others, she spoke a string of words they couldn’t understand.

“Are you Indigenous?” Penny asked curiously. “Can you speak Common?”

“Indigenous peoples” was the collective term for the continent’s original peoples, encompassing several distinct cultures. Long before the Cataclysm, many of them had lived in societies rooted in traditional hunting, herding, and wilderness survival.

Before the Cataclysm, they had been besieged and persecuted by modern civilization, forcing them into isolated reservations deep in the mountains, where they continued to preserve their own customs, clan structures, and ways of life.

They had also suffered during the global nuclear war, but because they lived far from the nuclear blast zones and were better adapted to surviving in the wild, their population had recovered and grown. Over time, they expanded their territory.

This was the first Indigenous person Finn, Olivia, or Penny had ever met. Penny only knew about Indigenous peoples from the stories told by her father, a wasteland hunter.

The girl studied the three of them carefully before speaking in broken Common.

“Thank you… grateful… for help. You… very good!”

So she could speak basic Common after all. She just wasn’t very fluent.

She introduced herself as Watcher Redhorn, a member of the Indigenous Redhorn Tribe.

She had been herding bison in the area when she encountered a convoy. The convoy killed her bison and shot her several times. Believing her dead, they buried her underground, hauled away the dead animals, and left.

“You were shot that many times. How are you still alive?” Penny asked, her eyes wide.

Watcher Redhorn pointed at her chest.

“I am one blessed with power by the Skycoil God. My life is stronger than cactus.”

“So you’re a mutant?” Olivia asked curiously. “Don’t worry. All three of us are mutants too. What’s your special ability?”

Watcher Redhorn flicked a finger.

Out in the vast wasteland, two sharp bamboo needles rose into the air under her control. They hovered, then began flying at high speed while emitting piercing whistles.

Small hollow chambers had been carved into the bamboo needles, turning them into whistles. Whenever they flew, they produced a sharp, shrill sound.

Meanwhile, a third needle—this one made of iron—quietly rose into the air. Its tip was slender and razor-sharp. It flew over without making a sound, then stopped above Watcher’s head.

Finn immediately understood.

The two whistling bamboo needles were decoys meant to disrupt the enemy’s senses. The silent iron needle was the real killing weapon.

Such tactics could certainly catch someone off guard in a close-range ambush.

Unfortunately, times had changed.

Who would bother competing with her in the art of throwing needles? No matter how clever her tricks were, an enemy could simply shoot her from a distance.

Watcher was deeply grateful to Finn for saving her. Eager for revenge, she pointed out the direction in which the convoy had departed.

Thus, their group of three became a group of four. They climbed into the off-road vehicle and sped after the armed caravan.

At dusk, the sun gradually sank behind the distant mountains, and the sky began to darken.

Watcher lay on the roof of the vehicle, scanning the distance through Olivia’s binoculars.

Suddenly, she slapped the roof excitedly and shouted,

“I found them!”