I started with a ship full of max-level veterans, and I'm just a complete noob.

When Jiang Ming finished writing the last set of dots and strokes, there were already four rows of symbols on the paper, and the tip of the pencil had been worn down.

The recording was only eight seconds long, but he listened to it eleven times, revising his judgment each time, comparing the blurry boundaries frame by frame with the pulse width on the oscilloscope, and finally confirming the dot-dash combination of all thirty-seven characters.

Four lines of symbols were neatly arranged in front of me, like a string of untranslated foreign sentences.

He glanced at the clock on the wall; it was 1:15 PM. More than four hours had passed since 9:00 AM.

Fang Xudong left at noon to bring back three meals from the cafeteria. The lunchboxes were left on a stool by the door and remained untouched as they grew cold.

Xiao Zhao turned to the page for the international Morse code chart in the Morse code quick reference manual and began to convert the dots and strokes written by Jiang Ming into English letters one by one.

The first twelve characters went smoothly; each combination could be found on the code chart, and the spelled letters were FISHINNETSEV.

The problem started with the thirteenth character; five consecutive combinations could not be found on the standard code table, and the arrangement did not conform to the international Morse code rules.

Xiao Zhao flipped through the manual twice, looked up at Jiang Ming, and shook his head.

"It's not standard encoding; the second half uses custom encoding."

Jiang Ming had anticipated this; the half-section of the codebook seized in the Northwest was meant to deal with this situation, but the codebook wasn't in his possession; it was in the Confidential Security Department.

He picked up the internal phone and dialed Director Wang's office number.

The phone rang six times before being answered. The person who answered was a clerk with a crew cut, who said that Director Wang was in the interrogation room and asked what was wrong.

Jiang Ming only said one sentence: "The subcarrier signal has been separated, and we need a codebook."

There was a two-second silence on the other end of the phone, then the crew-cut clerk said to wait.

While waiting, Jiang Ming wrote down the letters spelled out by the first twelve characters: FISH IN NET SEV. The fish is in the net; there should be more content after that.

The phrase "the fish is in the net" reminded him of something Director Wang had mentioned. On the night of Operation Iron Chain, when the ground forces surrounded the underground fortifications, the last plain text segment intercepted by the radio contained similar wording.

That was the last confirmation signal sent by the enemy radio station to its superiors, meaning that the target had entered the jamming coverage area.

However, the fact that this signal was hidden in the subcarrier and transmitted simultaneously with the main interference signal indicates that it was not sent to the frontline operators, but to another receiver.

At 7:40, there was a knock on the door of the confidential cubicle.

When Director Wang pushed open the door, he was followed by a man in his forties, wearing a gray-blue cotton coat and black-rimmed glasses. He carried a locked briefcase in his left hand and an unlit cigarette in his right.

Director Wang's introduction was brief: "Old Zhou, from the cryptography team, brought over some fragments."

Old Zhou nodded in greeting, placed his briefcase on the worktable, and took out a kraft paper envelope containing two things: a palm-sized piece of paper with charred and blackened edges, printed with a dense table of numbers and letters; and a handwritten note card indicating the coded area covered by the fragment and the speculation about the missing parts.

"This is half a sheet left over from burning in the underground fortifications." Old Zhou laid the paper flat on the table, pressing down the two corners with a paperweight. "It can cover about 60% of the custom codes, and the remaining 40% will rely on context inference and frequency analysis."

Jiang Ming pushed the four lines of dots and symbols he had recorded in front of Lao Zhou and pointed with a pencil to the position where the thirteenth character would begin.

"From here on, standard chronographs cannot be found."

Old Zhou bent down and leaned closer to the charred fragment, sliding his right index finger down line by line along the comparison chart.

The thirteenth combination, dots and lines, found its corresponding number 7 in the fourth column of the fragment.

The fourteenth one, dotted and drawn, the sixth column, the letter L.

The fifteenth one wasn't on the fragment, so Lao Zhou wrote a question mark on the blank paper next to it.

The sixteenth and seventeenth consecutive combinations were found in the second-to-last line of the fragment; they are the letters N and G.

Old Zhou's fingers skipped back and forth between the fragments and symbols for more than twenty minutes, eventually converting all thirty-seven characters into a mixed sequence of plaintext letters and numbers.

There are three missing parts in the middle, which are replaced with question marks, but the context is enough to make the meaning of the whole sentence clear.

Jiang Ming took the translation slip that Lao Zhou had prepared, read it from beginning to end, and then read it again.

The note reads:

The fish has been caught in the net. Lightning 7, backup frequency band 5.2MHz to 5.4MHz, frequency sweeping broadband suppression to begin in October. Source location: northern foothills of the Altun Mountains, No. 04 old mine shaft.

Director Wang stood to the side of the worktable without saying a word until Jiang Ming put the note down before reaching out to take it and read it.

After reading that line of text, his breathing rhythm changed, his shoulders tightened, and the knuckles of the hand holding the note tensed.

"Lightning Seven." Director Wang said these four words in a low voice, as if confirming with someone who wasn't there.

Jiang Ming knew what this code name meant.

Among the equipment seized during Operation Iron Chain, the magnetron nameplate had a serial number followed by a string of handwritten numbers, one of which was 7. At the time, no one knew what that 7 referred to.

Lightning Seven.

This was Lao Lei's project back then.

A radar research project that was terminated in 1949 during electromagnetic experiments in Northwest China was abandoned when the project leader died in an accident. All the data was sealed and the participants were dispersed and transferred. No one mentioned the name again for the next six years.

But the enemy agents brought it up, and not in the old files, but in an operational order that was being executed.

They not only knew about Lightning 7, but they were also using the research results of Lightning 7 to deploy jamming equipment.

"5.2 to 5.4 MHz." Fang Xudong walked to the table and pointed to the frequency numbers on the translation. "This is the shortwave high frequency band. The main frequency band used for long-distance communication at the Northwest base falls within this range."

Jiang Ming continued, picking up where Fang Xudong left off: "Frequency sweeping broadband suppression means that they are not interfering on a fixed frequency, but sweeping back and forth within the entire 200 kilohertz bandwidth. They suppress whichever frequency has communication, and the front line cannot avoid it by frequency hopping."

"Start in October." Director Wang slammed the note on the table. "Today is September 29th."

No one spoke in the cubicle; the second hand of the wall clock completed a full circle.

Old Zhou put the cipher fragments back into the envelope, put them into his briefcase, locked it, and stood aside waiting for instructions.

Director Wang turned to Jiang Ming: "Old Mine No. 04, on the northern slope of the Altun Mountains, do you know what kind of place that is?"

"The exact location is unknown, but there are old tungsten and copper mines left over from the Japanese occupation period on the northern slope of the Altun Mountains. The local garrison conducted a general survey and registration before 1949, and most of them have collapsed and been abandoned."

"Number 04." Director Wang repeated, "The number indicates there's more than one location; the enemy has marked at least four backup positions."

He folded the note, put it in his inner pocket, buttoned the flap, and turned to the crew-cut clerk, saying, "Draft a telegram, top secret, to be sent to the Northwest Base Communications Support Department. I will dictate the contents."

The crew-cut clerk took out a pen and a small notebook from his shirt pocket, holding the pen tip against the paper and waiting.

Just as Director Wang was about to speak, the soldier on duty at the door suddenly poked his head in, holding up a piece of paper and handing it to the crew-cut officer.

The flat-topped clerk took the note, glanced at it, his expression changed, and he handed the note directly to Director Wang.

Director Wang unfolded the note. It was short, containing only two lines of text, in the format of a telegram translation:

Urgent telegram from the Northwest Base: Starting at 11 PM on the 28th, intermittent broadband frequency sweeping interference occurred in the main shortwave band from 5.2 to 5.4 MHz. The interference lasted for four minutes and then disappeared. It is suspected to be a signal from enemy equipment debugging. Please investigate immediately.

The timestamp on the note indicated that it arrived at the Beijing Telegraph Bureau at 3 PM today, was transferred to the Confidentiality and Security Department, and entered the factory's reception room at 4 PM. The soldier on duty had just delivered it.

Director Wang placed two slips of paper side by side on the table. One was an enemy radio order that Jiang Ming had just deciphered, which stated that it would be launched in October. The other was a live report sent back from the Northwest, which stated that probing interference had already occurred on the night of the 28th.

"They arrived ahead of schedule." Director Wang slammed his fist on the table, causing the teacup to bounce and spill water, soaking the notebook next to it.

"Send the message immediately, don't wait until tomorrow, send it tonight." He turned to look at Jiang Ming, "Can that magnetron you have, Yuanlei-1, be used as a reference for locating the interference source?"

Jiang Ming did not answer immediately.

Whether Yuanlei-1 can serve as a reference is one thing, but the current state of chaos on the northern slopes of the Altun Mountains is another.

If the old mine shaft No. 04 has already started debugging equipment, it means that the transmitting antenna and power amplifier link have most likely been set up.

A light shining in Beijing doesn't necessarily illuminate a desert thousands of miles away.

"Send the alarm first." Jiang Ming pushed the enemy radio translation forward half an inch. "Get the Northwest region to send back the jamming strength, frequency sweep rate, receiver front-end status, and whether the direction finding station is still working. Without these, Yuanlei-1 can only sound in Beijing and cannot locate the Altun Mountains."

Director Wang glanced at him, but didn't ask any further questions. He turned to the crew-cut clerk and said, "Draft a telegram, top secret, urgent. Send it now."