A robotic voice echoed through the communication channel: "Abnormal entity detected. Execute the cleanup protocol?"

Chen Hao didn't move, his hand still resting on the joystick. He blinked, then turned to look at Nana, "Is this thing... asking us a question?"

Susan held her breath, her fingers gripping the edge of the recorder tightly. Carl slowly took a half step back, moving closer to the emergency power box, ready to cut off the signal source at any moment.

Nana didn't answer. Her pupils blinked rapidly, as if she were retrieving some data. A few seconds later, she raised her hand and lightly pressed the mute button on the control panel, turning off the external audio output.

“Don’t send any signals,” she said. “Now is not the time for dialogue.”

"Is it really going to wipe us out?" Chen Hao asked in a low voice, "or is it just bluffing?"

“It doesn’t seem like an attack precursor.” Nana stared at the screen. “Its questioning rhythm is perfectly synchronized with the barrier pulses, once every eleven seconds, with a stable interval. If it were a combat command, it wouldn’t use this frequency.”

"So it's a system process?" Susan interjected, "Like a startup confirmation?"

“Pretty much.” Nana nodded. “I suspect this is the final step in the authentication process. All those tentacles and signal prompts were testing our behavior patterns. Now that it has discovered we are not behaving normally, it has started the verification procedure.”

Chen Hao grinned, "So, all this running around like this actually got us approved?"

“That’s one way to understand it.” Nana opened the backend log and found the text she had cracked before—“Signal synchronization means channel is open.” She compared this sentence with the current voice packet and found that the data header structures of the two were the same, both containing the same encryption identifier.

“This isn’t a random warning,” she said. “It’s a pre-set response. As long as we send the matching signal in the right place, we can get through.”

"Let's do it then." Chen Hao released the control stick and stretched. "Anyway, it's annoying to sit here and wait for it to ask a third time."

“The problem is who will modify the signal generator.” Carl glanced at the toolbox. “It’s an old model, it works, but the frequency band parameters need to be rewritten, and a voltage regulator module needs to be added, otherwise it will burn out as soon as it starts up.”

"You take charge," Chen Hao decided immediately. "Nana and I will handle the location, and Susan will keep track of the times. Let's make sure we don't run into any new tricks."

Carl crouched down and opened the toolbox. The parts inside were a jumbled mess, but he quickly pulled out a gray-cased device with a faded label on the bottom: SG-7 Signal Simulator.

“It can still be repaired.” He disassembled the casing and checked the internal wiring. “The spare battery has power, and the crystal oscillator is not broken. It’s just that the output waveform is inaccurate and needs to be adjusted manually.”

"How long?" Nana asked.

"Ten minutes, if we're lucky."

"You have eight minutes." Nana glanced at the countdown timer. "The next pulse will arrive in nine minutes and twenty seconds. We need to complete the deployment before it begins."

Chen Hao stood up and walked around to the front of the main screen. The weak zone in the southeast was still flashing a red dot, about four thousand kilometers away from their current location. Not far, but flying at full speed in this area was tantamount to suicide.

“I’ll inch my way over,” he said. “Call me when you’re done.”

He gripped the control panel again and gently pushed the lever. The spaceship started at minimum power and drifted towards the target area like a leaf.

The cabin fell silent. Karl bent down to weld wires, a tiny white light emanating from the tip of his welding torch; Susan stared at the timer, which announced the remaining time every thirty seconds; Nana continuously refreshed the scan data, confirming that there were no new energy fluctuations around.

Seven minutes later, Karl took off his gloves. "All done. It can generate eleven-second periodic pulses, and it can last for three minutes without any problem."

"Continue," Chen Hao said without turning around.

Carl connected the device to the main console, and Nana immediately entered the startup sequence. A message appeared on the screen indicating a successful connection.

“The signal is ready,” she said. “We’re waiting for you to get there.”

Chen Hao advanced a distance, and the spaceship entered the weak zone. He shut down the engines and let the ship glide.

"We're here," he said. "What do we do now?"

"Wait for the next pulse start point." Nana looked at the waveform. "Three, two, one... Now!"

She pressed the send button.

The signal generator hummed, mimicking the original rhythm of the barrier, and a regular beeping sound entered space.

Everyone stared at the light screen in front of them.

The purple edge, which had been slowly rotating, suddenly paused for a moment.

The six energy tentacles hung in mid-air, no longer moving.

Immediately afterwards, the central area began to distort, and a thin crack split open from the middle, like a curtain being drawn back. Inside the crack, there was no bright light or explosion, only a calm, dark space, as if leading to another world.

"The passage is open," Susan whispered.

“And the door wasn’t closed.” Carl breathed a sigh of relief. “Looks like it really is a pass.”

"Shall we go?" Chen Hao asked Nana.

“Go,” she said. “Maintain the current speed, do not accelerate, and do not interrupt the signal.”

Chen Hao gently pushed the control stick, and the spaceship slowly entered the crevice.

The instant they passed through, everyone felt a sudden lightness in their bodies, like an elevator suddenly descending. The numbers on the dashboard jumped a few times before returning to normal.

The alarm lights went out, and the navigation system automatically updated the coordinates.

They came out.

Behind them, the ring-shaped light screen still floated in the star field, slowly rotating, as if it had never been disturbed.

“We’ve broken out of the buffer zone,” Nana confirmed. “All systems are functioning normally; no tracking signals have been detected.”

"You survived?" Chen Hao leaned back in his seat and let out a long breath. "I thought I'd at least be badly injured."

"You almost drained the battery." Carl put away his tools. "Don't go that wild next time."

"Even the most unskilled will find food," Chen Hao said with a smile, waving his hand. "Besides, didn't we succeed?"

Susan remained silent, staring at the communication screen, when she suddenly raised her hand. "Wait, the signal is back."

Everyone turned around.

A line of text popped up on the screen:

[Authentication successful. Welcome to the safe zone. The resource capsule is located at coordinates a-7. Please retrieve it within 24 hours.]

"There really is a reward?" Chen Hao's eyes widened. "I thought that 'signal synchronization means channel opening' was a hoax."

“It’s not a hoax.” Nana was analyzing the source of the data packets. “This system was built by humans, about three hundred years ago. The marking information shows that it belongs to the Joint Earth Space Agency’s Deep Space Navigation Project Group.”

"Left by humans?" Susan exclaimed in surprise. "Not aliens?"

“There are no records of extraterrestrial civilizations.” Nana shook her head. “All the encoding formats conform to the standard protocols of the old era. This should be an automated protection and guidance system used to protect important supplies or shipping lane nodes.”

"So..." Chen Hao stroked his chin, "the challenge we just overcame was actually a CAPTCHA set up by a programmer hundreds of years ago?"

“Logically, it makes sense,” Nana said.

"He's really bored," Chen Hao laughed. "Making such a big fuss just to block the road and collect admission fees?"

“Perhaps it’s to prevent AI from accidentally entering the system,” Nana added. “The system’s identification mechanism relies on unconventional behavior patterns. Standard flight paths are judged as threats, and only reckless behavior like ours can trigger the correct response.”

"So we're bug-type level-clearing players?" Chen Hao pointed at himself and Nana.

“To be precise, they are ‘unintended path users’,” Nana corrected.

"Call it whatever you want." Chen Hao stretched. "The key is—there are resources to get."

He looked at the newly marked coordinates a-7 on the main screen. The distance was less than 20,000 kilometers, and at the current speed, he could reach it in half an hour.

"Do you want to go?" Susan asked.

"What do you think?" Chen Hao retorted. "We just repaired the ship and then broke through a pass. Wouldn't it be fair not to pick up some things to make use of the electricity we've burned along the way?"

"Be careful on the road," Carl warned. "Who knows if there are other traps ahead."

"Don't worry." Chen Hao gripped the joystick again. "This time I won't wander off. I'll stay in a straight line."

The spacecraft activated its thrusters and moved smoothly toward a-7.

The atmosphere inside the cabin relaxed considerably. Susan put away the recorder, Carl leaned against the wall and closed his eyes to rest, while Nana continued to monitor the system status.

As Chen Hao operated the device, he hummed a song, completely off-key.

A few minutes later, Nana suddenly spoke up: "I've discovered something."

"Huh?" Chen Hao stopped humming.

"That last voice question..." she looked at the log, "...it didn't actually require our answer."

"ah?"

"The system unlocks the channel the instant we transmit the synchronization signal. The voice is just a remnant of the process; even if we do nothing, as long as we reach the location and send the correct frequency, we can still get through."

"It means..." Chen Hao realized, "When it asks 'Do you want to execute the cleanup protocol?' it has already decided to let it pass?"

“Yes.” Nana nodded. “It’s like an old-fashioned access control system. Even though the door is open, it still asks, ‘Are you sure you want to enter?’”

Chen Hao paused for two seconds, then suddenly burst out laughing, "So it's a talkative, silly system?"

“The technical term is ‘redundant interaction design’,” Nana said.

“I think it’s a case of severe obsessive-compulsive disorder.” Chen Hao shook his head. “No wonder it has stood for three hundred years without anyone repairing it.”

He pushed the lever again, and the spaceship accelerated forward.

The distant starry sky was calm, and the coordinates of a-7 were getting closer and closer.

On the control panel, the outline of the resource bay gradually became clear.

It was a cylindrical metal cabin, its surface covered with heat-insulating patterns, and the side was marked with a blurry number: Δ-9.

Chen Hao squinted and looked at it. "This look... it seems a little familiar?"

Nana retrieved the database for comparison, and the results popped up a few seconds later.

“Model matching,” she said. “This is the standard storage and transportation enclosure for the mK-3 fusion voltage regulator unit.”

"Wait a minute." Chen Hao looked up abruptly. "Is the energy device on our ship... also this model?"

"Yes," Nana confirmed.

"So the ship we painstakingly repaired might have been built using keys that someone else had already prepared?"