Chapter 1

Not long ago, I encountered the most difficult case of my police career.

The killer was cunning and ruthless, and had committed a truly perfect crime.

At a complete loss, I had only one person left to turn to...

My younger sister, dying and unconscious in a hospital bed.

The door to her room opened, and four people filed in.

I pointed to the four chairs and waited until everyone was seated.

“I've asked you here about Fu Nian's case. Don't worry. This won't take too much of your time.”

A girl with purple hair and tattooed arms gave me a resentful look.

“Haven't you already caught the killer? What did you call us here for?”

Her name was Fu Yi, the victim's younger sister.

Her own sister had been raped and murdered, yet I could see no trace of grief in her eyes.

Just then, a gentle, pleasant voice spoke.

“Officer Xia, you have my full support. If there's anything we can do to help, please ask.”

The woman was Bai Qiao, the victim's mother.

She was elegant and composed, a lingering sadness on her beautiful face.

The overweight middle-aged man beside her muttered a few disgruntled words but said nothing more.

The long-haired girl at the end of the row had watched me coldly and impassively from the moment she arrived.

I got straight to the point.

“The more I think about Fu Nian's murder in the art room, the more something feels wrong. The killer was caught at the scene, but I can't shake the feeling that there's more to this case.

“Unfortunately, I'm not very quick-witted. I've racked my brains and still can't work out what it is.

“I've asked you here for two reasons. First, all four of you were on the school grounds that night and never left. Second, you were the four people closest to Fu Nian. If I want to understand her, you're the best people to ask.”

Fu Yi interrupted impatiently.

“Then hurry up and ask. I've got plans later.”

I looked at her and slowly shook my head.

“I won't be asking you. She will.”

I pointed to the person in the hospital bed.

All four pairs of eyes immediately fixed on the girl lying there with her eyes shut.

Fu Yi frowned.

“Then wake her up. Stop wasting our time.”

“She won't wake up again,” I said quietly. “Terminal brain cancer. She's in a deep coma now.”

Before Fu Yi could lose her temper, the middle-aged man spoke.

“Officer Xia, if it weren't for your position, I'd have got up and left by now. How is someone who's unconscious supposed to help you solve a case?”

His name was Liu Jie. He was the school's vice principal, and Bai Qiao's boyfriend.

I could see his impatience plainly.

I stood, opened a drawer under their bewildered gazes, and took out a helmet.

Covered in wires and electronic components, it looked like something out of science fiction.

Then I switched on the computer beside the bed.

After a few simple operations, I picked up the helmet and explained.

“You may not know this, but research into brain waves is now quite advanced. With equipment that collects and amplifies the signals, we can accurately record the information they contain. We can even communicate in simple ways with patients in deep comas or vegetative states.”

They watched skeptically as I gently placed the helmet on my sister's head.

It flashed a few times. The indicator turned green.

I took her hand.

“Can you hear me?”

Beep!

A clear electronic tone sounded, and the computer screen turned green.

A question appeared on it.

“Is one plus one equal to three?”

Clunk.

At the dull sound, the screen turned red.

After a few more questions, I turned to the four visitors and smiled.

“As you've seen, I can communicate with her through this device and the computer. She can only answer yes or no, but that's enough to help me get to the truth.”

Fu Yi gave a scornful laugh.

“Officer Xia, have you been reading too many detective stories? You think you can solve a case with YES and NO? Is she Sherlock Holmes reincarnated? Detective Conan reborn?”

The others looked just as doubtful. I shook my head.

“Actually... you may know her. She's an alumna of your school, and my younger sister. The genius they called the ‘scourge of criminals,’ who helped police solve three nationally notorious cold cases before she was even an adult...”

Xia Ruonan.

As I said her name, I saw unmistakable flashes of alarm on several faces.

For the first time, the girl who had remained cold and impassive looked astonished.

She was Xu Ruo, Fu Nian's closest friend.

Following her disbelieving gaze, I looked at my sister. My nose stung.

Her skin was deathly pale, her cheeks sunken.

Her once-glossy black hair had all fallen out, leaving her scalp bare.

No wonder they were shocked.

No one could have recognized the emaciated patient before them, withered as rotten wood, as Xia Ruonan: the brilliant girl the police had commended, who'd stood before the entire school radiant with confidence.

She'd been cleverer than me since we were children.

Puzzles I couldn't finish, blocks I couldn't fit together, even homework I couldn't do...

To her, it was all simple.

I first discovered her gift for solving mysteries one afternoon.

I was watching a borrowed detective film, trying desperately to work out who the murderer was, when she pointed to someone I hadn't suspected once.

“That's definitely the killer.”

I laughed and stroked her head.

“How could it be? You don't understand this stuff. Just watch. No more talking.”

But when the film ended and the killer was revealed, I was astonished to find she'd been right.

“How did you know?”

“It's simple. He was... too normal. In a case like this, the more normal someone seems, the less normal they are.”

She was eleven.

Later, a series of crimes in our area shocked the nation.

Young women disappeared one after another, without a trace, as if they'd vanished from the earth.

The police mobilized enormous resources, but the killer remained elusive.

Using only the clues she saw on the news, my sister drew her own conclusions and sent a letter to the police.

It contained one sentence.

“Check the other households' water consumption.”

Following that lead, the police found a household whose water use was abnormal.

After his arrest, the killer confessed that he'd minced the women's bodies and flushed them down his household drains.

From then on, the police took a special interest in her talent.

She lived up to their expectations and went on to help solve several major cases.

It was her influence that made me become a police officer too.

But just when everyone thought a brilliant future lay before her, she fell ill.

Perhaps heaven envies the gifted.

She was diagnosed with brain cancer.

Her condition deteriorated, and she gradually slipped into a deep coma.

After a succession of treatments, even the country's finest brain specialist could only shake his head regretfully.

I transferred her to a small hospital near my workplace.

That way, I could visit every day.

Normally, the brain-wave reader was the only way we could exchange a few simple thoughts.

If this case hadn't left me utterly at a loss, I wouldn't have troubled her.

I shook my head and pulled myself out of those memories.

It was getting late.

Time to begin.

I looked over the four people before me, then slowly sat beside my sister's bed.

Taking her thin, bony hand, I began.

“Ruonan, I'll explain the whole case to you now.”

Beep.

Green light flashed across the screen.

I'd been over this case so many times that I could recite it without looking at the file.

“Three days ago, in the early hours of May sixteenth, at one thirteen, a guard on patrol at No. 1 High School noticed that the art room lights were still on.

“He thought someone had forgotten to turn them off and went in to do it.

“Inside, he found a male student on top of a female student, tearing her shirt. She was naked below the waist, her eyes closed, with a large pool of blood beneath her head.

“The guard immediately restrained him and called the police.

“That's how the case came to light. Do you need me to repeat it?”

Clunk.

The screen turned red.

“All right, Ruonan. Next, I'll describe the scene and give you the victim's and suspect's details.

“When we arrived, the scene hadn't been disturbed. The victim was lying on her back, with paintbrushes scattered around her. A bloodstained bronze horse statuette lay on its side beside the body.

“The boy in custody was deathly pale, trembling all over, and unable to speak.

“The preliminary examination indicated death from a heavy blow to the head with a blunt object, causing a depressed skull fracture and bleeding in the brain.

“We initially identified the bronze horse as the murder weapon.”

Beep! Beep! Beep! Beep! Beep! Beep!

A series of electronic tones suddenly rang out. The screen kept flashing green.

“Ruonan...” I asked hesitantly. “Do you want to ask something?”

Beep.

“You only signaled when I mentioned the horse... You want to ask about the statuette?”

Beep.

A thought struck me.

“Are you asking whether it's the one you left at school?”

Beep.

“Yes. It's yours.”

My sister had brought it back from a trip abroad.

A little horse with its wings spread, poised to take flight. Two beautiful gemstones were set into its eyes.

Back then, she'd loved painting and chaired the school's art club.

After getting into university, she'd left the statuette in the art room as a wish for the younger students: that their imaginations might soar as freely as a winged horse, and that they might find success.

But why ask about it now?

Whether it was hers clearly had nothing to do with the case.

And my sister would never ask an irrelevant question.

Suddenly, an idea flashed through my mind.

My eyes brightened slightly. I calmly glanced at the four people before me and went on.

“Any other questions, Ruonan?”

Clunk.

The screen turned red.

“Then I'll continue.”

Beep.

“The victim was Fu Nian, a student in No. 1 High School's advanced class. She was an excellent student with a gentle disposition, and had ranked first in her year throughout all three years of high school.

“When she and her younger sister, Fu Yi, were little, their parents died in a car accident. Their mother's close friend, Bai Qiao, adopted them.

“Bai Qiao is the homeroom teacher of the advanced class. She remained unmarried all these years to look after the two girls.

“Fu Nian wasn't very sociable. Her one close friend was Xu Ruo, also in the advanced class. Together, they consistently occupied the top two places.

“Xu Ruo is also sponsored by Bai Qiao, who's paid all her tuition and living expenses since junior high.

“The suspect in custody is Xiao Chen, another student in the advanced class. According to his classmates, his crush on Fu Nian was an open secret.

“That's the background, Ruonan. Any questions?”

Clunk.

The screen turned red again.

“All right. Next, the traces at the scene and the autopsy findings.”

I quietly looked over the four visitors. Nothing unusual caught my eye.

“The art room gets so much traffic that the footwear impressions were difficult to distinguish and catalog.

“The autopsy confirmed that the bronze horse was the murder weapon. It struck Fu Nian's temple, depressing the skull and causing severe bleeding in the brain.

“Strangely, the only fingerprints on it belonged to Fu Nian.

“Furthermore, she'd been sexually assaulted before her death. There were genital lacerations, and Xiao Chen's fingerprints were on her body. However, no semen was found in her vagina.

“Our initial theory was that he'd used a condom and disposed of it. But after confessing, he refused to say another word.

“Finally, the forensic team found a phone and a bloodstained photograph in Fu Nian's pocket. The phone contained no clues relating to the case. The photograph showed her with Fu Yi.”

Fu Yi's face immediately went white.

She quickly recovered, but her faintly trembling fingertips betrayed her composure.

I knew she was hiding something.

“That's everything. Any questions?”

Beep.

The screen turned green.

“What about, Ruonan? The footwear impressions?”

Clunk.

“The statuette used as the weapon?”

Beep.

“You mean... you're wondering why the killer's fingerprints weren't on it?”