Ice skates forward, regardless of east or west.

1

The tape spun under the car, making a rustling sound like tiny claws scraping against metal.

Gu Xidong's hand froze in mid-air, his fingertips still feeling the cold touch of pressing the play button.

Zhou Wentao's voice echoed in the carriage, each syllable piercing the eardrums.

"Xiao Ling, curiosity killed the cat."

Ling Wuwen moved first. She picked up the tape recorder and pressed the stop button. The noise stopped abruptly, and the carriage fell into an even more terrifying silence.

"Keep listening," Gu Xidong said, his voice dry and cracked.

Ling Wuwen is playing again.

After a brief pause, Zhou Wentao's voice rang out again, this time gentle and concerned:

"You're young and have a bright future. There are some things you won't benefit from knowing. Remove the list, and come to my office tonight to talk."

Ling Wufeng's voice was tense and clear: "How did you manage to make Gu Xidong 'accidentally' withdraw from the competition? How many other people on the roster will have their careers ruined?"

"I made copies, more than one. If something happens to me, the backups will be automatically sent to seven email addresses, including the General Administration of Sport's Discipline Inspection Commission and the International Skating Union."

There was a ten-second silence, with only the sound of the tape turning.

Then Zhou Wentao laughed.

The laughter was distorted and hoarse, carrying an inhuman chill.

"You're smart, smarter than your brother. But smart people often die faster."

The tape reached its end and popped up with a "click".

The carriage fell silent once more.

Gu Xidong stared at the black recorder, his brain frantically piecing together information: the list, backups, seven email addresses. Ling Wufeng had already prepared a backup plan.

"Seven email addresses," Ling Wuwen said, his voice tense. "Who did he send them to?"

"I don't know. But if the backup was sent, why has there been no news for three years?"

The two looked at each other, and the answer emerged in the silence:

Either it wasn't sent in time, it was intercepted, or the recipient was already online.

Morning light streamed through the car window, casting pale patches of light on the tape recorder. Gu Xidong picked up the box; a yellowed label with handwritten numbers on the bottom read:

7-22-19-1-14-7

"Password?" Ling Wuwen leaned closer.

"Each group is between 1 and 26, possibly in alphabetical order."

Gu Xidong's quick conversion: 7=G, 22=V, 19=S, 1=A, 14=N, 7=G.

GVSANG – meaningless.

"Try it upside down." Ling Wuwen typed into his phone, "GNASVG, it doesn't make sense either."

"V might be the Roman numeral for 5."

顾西东重新换算：7-5-19-1-14-7 → G-E-S-A-N-G。

"German," Ling Wuwen's breath hitched, "Gesang means 'singing'."

Singing. Music.

A flash of inspiration struck Gu Xidong—three years ago, during the competition, he and Ling Wufeng chose Saint-Saëns' "The Swan" for their free skate. Ling Wufeng had once said that the piece held a "secret."

"The Swan," Gu Xidong blurted out, "the one from Saint-Saëns' Carnival of the Animals. Lin Wufeng once said that the arrangement of piano notes is like a code."

He closed his eyes and recalled: In the training hall's lounge, the setting sun shone through the blinds, and Ling Wufeng pointed to the video on the tablet and said:

"If one day I have something to tell you but don't dare to say it directly, use this. Listen to sections 7, 22, 19, 1, 14, and 7; put them together and you get the message."

"Where is the sheet music?" Ling Wu asked.

"My old apartment is sealed off. But I know who still has it."

Gu Xidong pulled out dark blue ice skates. On the inside of the sole, there was a line of small print: "Spicy Hot Pot Restaurant, No. 27 Mianhua Hutong, Dongcheng District, Old Zhao who plays the piano every Wednesday." The tongue was abbreviated as ZX.

"Zhao Xun. Three years ago, he was the runner-up in the National Championships, but retired after rupturing his Achilles tendon."

Ling Wuwen started the car, the tires rolling over the wet pavement. The streets were deserted in the early morning, everything seemed normal, only they knew that the time bomb from three years ago had begun to tick.

"If Zhou Wentao knew Lin Wufeng was recording," Ling Wuwen looked ahead, "why did he still let him go on stage? Why didn't he just kill him?"

"Because the recording wasn't a lethal threat. Ling Wufeng had the list and backups, but they needed to be deciphered. Zhou Wentao probably thought the secret was sealed away because the person was dead, unaware that he had left clues for me."

2

The car turned into a hutong in Dongcheng District.

Blue bricks and gray tiles, clotheslines hanging with dripping wet garments.

At No. 27 Mianhua Hutong, the wooden signboard with the words "So Spicy You'll Cry" is written in illegible handwriting. The shop door is tightly closed, and the roller shutter is pulled all the way down.

Footsteps echoed from the depths of the alley. A man in a sports vest, around forty years old, ran up, his right leg slightly uncoordinated as he ran. He stopped at the shop entrance, his gaze sweeping over Gu Xidong and Bingxue.

"Gu Xidong," the man said.

"Zhao Xun".

Zhao Xun unlocked the door and pulled up the roller shutter, gesturing for them to enter. The restaurant was filled with the smell of hot pot broth and disinfectant.

He turned on the floor lamp, illuminating the piano, on which lay the sheet music for Saint-Saëns' "Carnival of the Animals".

"The shoemaker sent you." Zhao Xun poured three glasses of water.

"I pawned those shoes to him three years ago. He said someone would come looking for me with them."

Gu Xidong placed the ice skates on the piano bench. "We need you to play 'The Swan'."

Zhao Xun sat down at the piano, her fingers hovering over the keys.

"Three years ago, Ling Wufeng came to see me a week before the competition. He gave me the sheet music and said that if something happened to him, he would record me playing measures 7, 22, 19, 1, 14, and 7 separately and send it to me."

Did you send it?

"It was sent, an anonymous package to your national team dormitory. But I heard you weren't in good form at the time, so the package might have been returned or lost."

Zhao Xun took out a handwritten musical score from under the piano lid, which was stored in a transparent file bag.

The neat handwriting was Ling Wufeng's, and the string of numbers was written in pencil above the section.

Gu Xidong ran his fingers over the yellowed paper. "Play it."

Zhao Xun's finger fell.

As the first note sounded, Gu Xidong closed his eyes. He was familiar with the piece and only now could he hear the distress signal hidden within the notes.

Section 7: Rapid triplets.

Section 22: The slowed melody is like a sigh.

Section 19: A deep, dull bass line is introduced.

Section 1: Pure Theme.

Section 14: The high notes rise sharply.

The seventh section again: even more urgent and chaotic triplets.

The last note faded away.

"What did you hear?" Ling Wu asked.

Gu Xidong shook his head. "It needs to be converted into letters."

Zhao Xun pulled out a folded piece of paper. "Ling Wufeng left a conversion table, with each note corresponding to a letter. He said it was the password you used to play games when you were kids."

The note was written in childish scribbles, and each key on the piano keyboard was marked with a letter. Gu Xidong, trembling, translated it by referring to the sheet music:

Section 7: G, E, C

Section 22: A, D

Section 19: F, B

First section: C

Section 14: E, G, A

Section 7 again: G, E, C

Put together: GECADFBCEGAGEC — meaningless.

"Look at the note values," Ling Wuwen pressed his hand down, "Does Ling Wufeng know how to distinguish them using note values?"

Gu Xidong marked the time values: whole note = 1, half note = 2, etc. The resulting number sequence is still meaningless.

"No, something must have been missed."

Zhao Xun walked behind the bar, turned on the CD player, and played Bach's "Air on the G String".

As the music played, Gu Xidong suddenly looked up.

"It's not a single piece, it's two pieces stacked together. Ling Wufeng likes to listen to the two pieces together to create a 'hidden harmony'."

"What's the second song?"

Gu Xidong looked at Zhao Xun. Zhao Xun pulled out another sheet music from under the piano bench—Chopin's "Farewell Song".

Gu Xidong quickly flipped to the same section and hummed two melodies at the same time.

When notes overlap, a new note is created. He calculated the corresponding numbers for intervals: a major third = 4, a perfect fifth = 7, a minor second = 1...

The resulting number sequence is: 4, 7, 1, 9, 14, 7

Letter conversion: 4=D, 7=G, 1=A, 9=I, 14=N, 7=G

DGAING—still meaningless.

Gu Xidong slammed his fist on the piano, the keys producing a piercing chord.

"Calm down," Ling Wuwen patted his shoulder, "Ling Wufeng wouldn't set a password you can't crack. It must be something you know but didn't think of."

Gu Xidong stared at the letters GNIAGD, his gaze settling on "IA".

"Pinyin?" He quickly wrote Chinese characters: G=brother, NI=you, A=ah... Doesn't make sense.

"Tone," Zhao Xun suddenly spoke, "Ling Wufeng has an accent. Do musical intervals correspond to tones?"

Gu Xidong was startled and tried to read it aloud again, but it still didn't work.

3

Despair spread. Gu Xidong looked down; there was a line of tiny pencil writing in the corner of the sheet music.

He held it up to the light, and the blurry words gradually became clear:

"Read it backwards, using our code."

The code—invented at age thirteen, each letter is moved forward three digits.

Gu Xidong moved each letter of GNIAGD forward three positions to get JQLDJG, which is meaningless; he moved it backward three positions to get DKFXDA, which is still garbled.

He opened his eyes and saw the doodle on the last page of the sheet music: a simple swan with its neck bent into a question mark.

"It's not the alphabet, it's shapes."

He arranged the six letters along the curve of a swan's neck and read them from the top along the curve: G, I, A, G, D, N → GIAGDN.

Pinyin: G=哥, I=一, A=啊, G=哥, D=的, N=你 → 不通.

"Speed ​​up recording with tone combination." Ling Wuwen turned on his phone to record.

Gu Xidong recorded himself reciting letters according to the tones of each interval. Playing at double speed, the indistinct phrase: "Brother, ah, brother you..." Playing at triple speed: "Brother, ah, brother you..."

"Brothers. Brothers."

Speeded up four times, six tones emerge as a clear and complete sentence through extreme compression—

"Brother, save my life!"

Time stood still.

Piano dust floats in the morning light.

The glass in Zhao Xun's hand slipped and shattered.

Gu Xidong stared at the tape recorder, the sheet music doodles, and the cry for help that the boy had buried in despair three years ago, a cry that only he could understand.

Ling Wufeng knew he would die. So he used childhood secrets, shared melodies, and invented games to leave behind his last words.

It wasn't a clue, it wasn't evidence, it was a cry for help.

Gu Xidong finally heard it on this morning three years later.

The sound of screeching brakes came from the alley outside the shop.

Ling Wuwen quickly turned off the lights and pulled down the roller shutter.

In the darkness, the three breathed in sync.

The footsteps stopped outside the door. A knock sounded, three polite knocks.

Then came a gentle, familiar voice that Gu Xidong would never forget:

"Gu Xidong, I know you're in there."

Zhou Wentao said through the door:

"Let's talk about the list your brother left behind...."