The hospital is quieter at night than during the day. The smell of disinfectant in the hallways combined with the quiet of the night always felt almost mournful. The black-haired man sat alone on a bench in the smoking area, staring like a sculpture at the foliage plants next to the vending machine opposite, the white filter cigarette between the fingers of his left hand and a misty mist building up above the scarlet firelight.

"Smoking so many cigarettes again......"

A faint and helpless female voice sounded beside him, and then a figure in a hospital gown sat heavily into the seat beside him. The man's fingers shook slightly, and he turned his face sideways and smiled at the girl beside him, "Have you finished making the record?"

"Hmm. The girl's gaze swept over the six or seven cigarette butts in the ashtray, and her brows were twisted together by Liuhai, "What a strange case...... The prisoner seems to be very familiar with the terrain of the school, and not only the Ice Emperor, but also the other victims were attacked at the school. There was no connection between the victims other than that they were also primary school students, and none of the victims were fatal. What exactly is the murderer trying to do?"

"There are also various kinds of human psychology, especially in this day and age. Matsuda curled the corners of his mouth, and there was a hint of sarcasm in his words, "This is a so-called social problem." ”

"Social Issues...... It's really ......," Nao snorted from her nose, "If I only attack Natsu alone, I still have the direction to investigate, and a social problem really cuts off all the ways." ”

"Well, don't say that, there's going to be somewhere left......" Matsuda Jinpei's deep eyes narrowed, "that small, dirty piece of the puzzle that would allow us to find him." ”

"But the key for now is Natsu's safety," Nao remembered her sister's bloodless little face, and her golden-green eyes were stained with deep worry, "Unlike the others, Natsu seems to be the only victim who sees the prisoner." The others were attacked without anyone noticing, only she made a noise when she was attacked, so ......"

"You're saying it's possible that Miss Natsu saw the face of the prisoner?"

"No, at best, it's just stature and features. Nao shook her head in dismay, "When I rushed in, I saw the prisoner, he was wearing a hood and a mask, and he couldn't see his face at all. But Natsu was wounded more than any other victim, and she would have been killed! If I hadn't arrived in time, she would have ...... So there's a good chance she saw something that the prisoner could reveal his identity. ”

Nao's voice trembled a little as she said these words.

The other elementary school students who were attacked, a total of five except Natsu, were stunned by ether and then wrapped around their necks with nylon ropes. But they were not fatally attacked, and the rope was only lightly wrapped around their necks. In addition to Natsu...... Except for Natsu, who was strangled around her neck by a nylon rope as thick as two thumbs and hung from the door like a hanged corpse. Nao's uninjured right hand gripped her knee tightly, and her joints were a little white. The thought of Natsu's assault makes her whole body tremble.

She was scared.

She had just sneaked out of the ward to see Natsu, who was still unconscious. Her sister lay quietly on the bed as if she were asleep, but the shocking bruise on her neck destroyed all her sense of peace and tranquility. Dense bleeding spots wrapped around her neck like a snake, and there were actually traces of patterns on the nylon rope behind the neck-

What does this mean?

This represents that the prisoner had strangled her with a rope before, and this practice had to be stopped because of Nao's sudden appearance and instead of hanging her - an outright murder! If Natsu hadn't had time to scream, if the cry hadn't reached Nao's side in time, if she hadn't arrived at the scene of the crime in time, if she hadn't been able to break down the door in time when she arrived at the scene, Natsu would have ......

It will ......

"Damn...... It's all my fault...... If I hadn't let her go alone......"

Nao's voice felt like it had been smashed by a sledgehammer, sharp shards stabbing into her throat and her nose, and it hurt so much that every word she said felt like a knife was being slashed. Matsuda Jinpei gently lowered his eyelids and looked at the bright red in front of him, the corners of his lips curled up as if relieved, and he stretched out a hand and rubbed the top of the girl's head,

"You've done a great job, stupid. ”

"Well done? Hey, don't comfort me. Nao let out a self-deprecating sigh, "I'm nearby, but I still let her suffer this kind of thing, so what is the purpose of me picking her up? If I hadn't gone in with her, how could Natsu ......?"

"You're just too, silly girl. Matsuda lowered her head in dissatisfaction and curled her lips with a light smile, "No one can foresee danger like a god, and no one can make a lifetime of peace. But even if you really anticipate the danger and are prepared, there is no 100% chance of success. All you can do is do everything you can to minimize the impact of danger when it comes, and think about ways to remedy it after it happens, and that's it. Of course, there are occasional unforeseen things that happen...... Hawkers,As long as you're not as arrogant as that guy.,The chance of appearing is like a □.。 ”

"Don't say it so easily, no one will be relieved if they encounter this kind of thing. Nao smiled absently, shook off Matsuda's hand on her head sideways, and stood up with a chair, "All in all, I won't let go of the murderer who hurt Nao, I'll go to the scene tomorrow to see." ”

But even the small act of "standing up" had already touched the wound on her left arm that had just been stitched up. Nao involuntarily pressed on the injured shoulder socket and took a deep breath as if she was enduring something. Matsuda Jinpei looked at her face that turned pale from the pain, chuckled a few times without warmth, patted his pants and stood up.

"No, I can't. Investigating this case is a search lesson, and your current task is to heal your wounds. He took out his cigarette case, flicked a cigarette to his lips, and looked down at the girl beside him, "It's already the limit to let a patient who has just undergone surgery sit here, whether you want to find clues or what you want, at least for a week." ”

"Even if you say that...... "The dull pain in Nao's shoulder socket became more and more intense, and her eyelids became heavier and heavier, and she could even feel her own blood rushing against the wound that had been stitched up. A darkness rushed into her retina, rumbling deep in her ears. She staggered and grabbed Matsuda's sleeve and shook her head with a sudden deep sleepiness, "Why is this happening...... What medicine did the doctor give me?"

"You're a normal reaction to blood loss. Matsuda smacked his lips gloatingly, "So you're going to be honest, idiot." ”

"Go to the scene......" The girl who was already a little dazed in her eyes responded.

"you. ”

Matsuda burst out laughing, leaned over and picked up the girl who was no longer able to control her body, and strode towards the ward.

By the time Nao came to consciousness again, it was already noon the next day. She opened her eyes and looked around, only to find that Matsuda Jinpei was not around, only a bulging brown paper bag and a glass of water lying on the bedside table next to the hospital bed. Nao sat up with her right hand propped herself up, moved her already burning throat, grabbed the cup of water that she could reach without much effort, and poured it down.

"Warm. She licked her lips and grunted, put the cup back in place, and picked up the brown paper bag beside her.

Pulling open the line at the mouth of the bag, a pile of one-time imaging photos slid out of the bag, and a few printed texts were lying at the bottom of the bag. Nao raised an eyebrow and set the bag aside, picking up the photograph and looking at it as if it were bland—the broken door, the wide open window, the water-stained floor, the broken plants in the flower beds under the window...... Looking at these photos of the scene, the corners of her mouth unconsciously curled higher and higher, and finally curved into a pleasant arc when she saw the black mobile phone in the photos that was placed on the ground to temporarily compare the size of the evidence.

"It seems that the only reason to go to the scene has been eliminated. Nao shook her head with a wry smile and took out the text in the paper bag.

The content of the text is not very complicated, and most of them are news clippings about the attacks on minors that have occurred in the past few days, interspersed with simple information about the victims and photos of the scene. Although this information is still lacking compared to the information in the Metropolitan Police Department's database, for Nao, this simple but direct information to the center of the case is the most suitable information to facilitate the identification of several common points of the victims.

That's right, the commonality.

Any crime is purposeful, and this case is just a "minor" that seals the possibility of the offender committing the crime indiscriminately. Although the victims may not seem to be connected, and their schools, hobbies, and genders are different, there is certainly one thing in common that can attract the attention of the inmates. Now that the roots of these commonalities have been dug up by Matsuda Jinpei, all she needs to do is smooth out the tangled roots and tendrils of them, and finally find the rhizome that connects the threads.

[Kamitono Chika, 10 years old, female, a fourth-grade student in the elementary school of the private green garden school in Kakudocho, was found at 5:23 p.m. in the park 200 meters away from the school, anesthetized by ether, no injuries, and no traces of prisoners were found. 】

[Kuraoka Daisho, 9 years old, male, a third-grade student at the elementary school of St. John's School in Rice Flower Town, was found next to the garbage dump in the school at 4:55 p.m., anesthetized with ether, no injuries, and no traces of prisoners were found. 】

[Mei Wuto, eleven years old, female, a fifth-grade student in the elementary school of the private Didan School in Rice Flower Town, was found next to the warehouse in the school's breeding room at five o'clock in the afternoon, anesthetized by ether, no injuries, and no traces of prisoners were found. 】

[Yuto Hirano, 10 years old, male, a fourth-grade student at the elementary school of the private Taigang Gakuen in Kakuto Town, was found at 5:37 p.m. in the alley behind the shopping street near the school, no injuries, no traces of the prisoner were found. 】

[Saotome Natsu, 11 years old, female, a fifth-grade student at the elementary school of the private Ice Emperor School in Kakuto Town, was found in the bathroom of the school at 5:40 p.m., was anesthetized by ether, strangled by the prisoner, and was in a coma, and the prisoner escaped through the window in the bathroom. (Note: The scene was destroyed by the first discoverer, and no traces of the prisoner were found.) ）】

Nao's fingers rhythmically tapped on the last line of the document, squinting at the mocking note at the end.

"The scene was destroyed" she could understand, but she disagreed with the sentence "no trace was found". No matter how clever the prisoner is, will he not leave any traces on the way to escape in a hurry? Even if there are no fingerprints and no hair, the floor of the toilet is wet, and the prisoner will not leave any footprints after turning out of the window? If there is a concrete floor outside the window, it is easy to say that the wet footprints are easy to evaporate and disappear, but the fact is that it is ......

With two fingers, she picked up a photograph of what it was like outside the bathroom window—a mess of flowers, wet footprints on the ground. As can be seen from the close-up of another flower bush, the broken flower stem is covered with footprints of various patterns. "The forensic department does not seem to have found any discernible footprints in the ground beneath the stems, so they step on them without hesitation to collect fingerprints on the windowsill. She found this line on the back of the photo, and it was written by Matsuda Jinpei.

"Heh, I don't know, I think that the people of the Ice Emperor have a habit of coming out of the window of the toilet. Nao smiled, looking carefully at the close-up of the footprints. What attracted her to look at it was none other than the mobile phone that Matsuda Jinpei used to compare the size of the exhibit in the photograph that lay flat on the ground - and the object being compared was a small hole one centimeter in diameter next to the carrying phone.

"What is this?" Nao muttered confusedly, flipping the photo to the back with her backhand, and sure enough, there was a line of annotation on it: "Visually 0.9cm in diameter." Exhibit 1 was found in the cave, and fingerprints could not be identified because it was wrapped in dirt. ”

Nao looked at the sentence "Exhibit 1" and was stunned, and hurriedly picked up the paper bag on the side and shook it upside down. Sure enough, a small evidence bag fell out of the mouth of the bag, with the symbol "1" written on the mouth of the bag with a black pen, and the bag contained an orange oval crystal the size of a mung bean.

"It's ...... Topaz?"

"Yo, Miss Detective, are you fascinated by the story?"

A male voice mixed with many dialects sounded, which really startled Nao, who was immersed in thought. She looked up with wide eyes and saw that the door to the hospital room had been opened at some point. A silver-haired teenager in a dark blue T-shirt leaned against the doorframe, squinting at her with a smiling smile.

"Werewolf-san?!"

"Finally found my deposit, I've been standing here for a long time!" the silver-haired boy chuckled and walked into the door, waving the plastic bag in his hand, "Oh, condolences." ”

"There's no need to bring anything like this, it's just a little skin trauma. Nao shrugged his shoulders as if in trouble, but he was extremely happy in his heart. Nioh Masaharu listened to Nao's long-lost Okinawan accent, and couldn't help but stretch out his hand and rub the girl's messy red hair, and teased with a face of vicissitudes, "Yes, 'just', 'a little', 'skin trauma', 'just'...... It turns out that you didn't lose blood and almost hung up, what a good boy, good boy. ”

"Hey!" Nao slapped off the paws on the top of his head and looked at him dissatisfied, "I said what was the matter with your old man's tone!, if I was really going to hang up, could I still sit here and let you pat my head?"

"You can't deny it, Miss Detective. Nioh withdrew his hand and waved his index finger at her, "It's been on the news this morning, 'Another attack by the chokeholder, the victim Saotome was in a coma due to ether poisoning, and her sister was injured while rescuing the trapped victim and is currently in hemorrhagic shock. ’。 Yanagi and Chuanzi-san called as soon as possible, saying that your portable phone was turned off, and let me try to contact you. But seeing that you are still so alive, I really doubt the authenticity of the news. ”

"Yanagi and Kawako-san also know?"

"Yes, but Yanagi still has club activities, and Chuan Zisang also said that he can come to see you in the afternoon. Nioh sat down beside the bedside and picked up the photos and documents scattered on the bed and looked through them. Nao listened to Nioh's explanation and nodded, but then thought of something, "Then you don't have any club activities today?" ”

"Ah, it's gone. Nioh shook his head indifferently.

"Skipped?!...... you really are," Nao held out her hand to him weakly, "Give me your minister's number." ”

"Don't think about that," Nioh squinted his eyes and pursed his lips at Nao, raising the materials in his hand, "Isn't your task now to study these materials? ”

That being said, I still don't have a clue at the moment. As soon as the case was mentioned, Nao stopped dwelling on the question just now. She picked up a close-up photo of the flower bed and handed it to Nioh, sighing a little dejectedly, "Can you see what this is?"

"The hole next to the phone?" Nioh took the photo, and while looking at it, he habitually played with the braid on his shoulder, "It looks quite deep, it seems to be a trace left by the tip of an umbrella." ”

"But as far as I can see, the prisoner didn't have an umbrella...... And even if it's an umbrella, what is its purpose?" Nao paused, holding up the plastic bag containing the evidence in his hand, "And this one, found in the cave, no matter how you look at it, it is a gem that has fallen from the ornament. ”

"No, it's not a gem," Nioh said confidently, turning his head to Nao as he shone his bag into the light, "it's citrine, and it's a high-grade with very few impurities. Orange citrine is native to Africa and is scarce and very expensive. ”

"......," Nao's throat moved, "Are you sure?"

"Of course," Nioh smiled wickedly, "my eldest sister is an expert in this area. ”

"What is known is that someone (or a prisoner) dropped this expensive citrine in a flower bed, and the prisoner poked it with something resembling the tip of an umbrella and pierced it into a hole as he escaped. Nao rubbed her temples, "But what is the purpose of this? Was the prisoner intentional or unintentional? Assuming he was unintentional, could it be understood that the citrine was accidentally left behind by the prisoner? or ...... The prisoner threw this crystal into a hole he had made for some reason?"

"Turning around, the problem is back to square one. Nioh tossed the evidence bag in his hand and raised an eyebrow at Nao, "Anyway, is that hole really left by the prisoner?"

"That's right," Nao nodded, "A single unnatural trace at the scene of the crime may be a clue to the detection of the case, especially a place that ordinary people will not set foot in." Moreover, the police questioned the gardener who took care of the flower bed, and according to him, the flower bed was still intact at noon on the day of the crime, so it is very likely that the hole and citrine were left by the prisoner when he escaped. ”

"Whew...... I said Miss Detective, let's take a look at the other information first. No matter how much you meditate on this hole, it won't tell you what it is. "It's better to wait for Chuan Zisang to come and ask her in the afternoon, maybe there will be some breakthrough." ”

"Chuan Zisan, why would she know?"

"Didn't I say that?" Nioh blinked, "Kawako-san is a costume design major like my eldest sister, and knows a lot about jewelry. If she spoke, she might know the origin of this crystal. ”

"I didn't say it at all...... However, it is also true. Nao sighed helplessly, and then laughed again, "That's ...... from the victim's information first."

However, before Nao could finish speaking, he was interrupted by the sound of the door opening.

Aiko Matsuda, with a happy face, hurried into the room, smiled at Nioh without surprise, and then said enough news to make Nao ecstatic.

- Natsu woke up.