2
Yuma lay on his back in the bed, staring at the ceiling. It was almost noon.
Several hours had passed since Kagami had swallowed the poison and died. Now that the culprit of The Glass House Murders was dead, there was no longer any danger, so the survivors all waited in their rooms for when the police would arrive that evening.
Returning to his room, Yuma took a hot shower, changed into clean clothes, and lay down on the bed. However, whether it was because he'd overslept the previous night or because his nerves were on edge, he didn't feel at all tired. When he closed his eyes, the nightmarish events of the past four days appeared before his eyes, so he just kept staring at the ceiling.
Although things hadn't gone at all according to plan, he had managed to kill Kozushima and avoid being accused of the crime. Now his sister could get her treatment.
Kozushima had been a serial killer who'd locked people in an underground dungeon and performed human experimentation on them. He deserved to die. And Kagami had clearly said he'd intended to take his own life after exposing Kozushima's crimes and eliminating his accomplices.
He'd done nothing wrong. What he'd done wasn't wrong.
He'd been repeating that to himself like a hypnotic mantra for the past few hours, but the guilt of committing murder, humanity's ultimate taboo, hadn't diminished.
Would there ever come a day when he could drop that heavy cross? Or would he be tormented by guilt for the rest of his life?
As he asked himself that, there came a knock on the door.
Who was that? Yuma got out of bed and approached the door. From the other side came the voice of the great detective, asking
“Yuma, may I talk to you for a moment?”
“What's the matter, Ms. Aoi?”
Yuma unlocked the door and opened it.
“Well, I've got nothing but time right now, so I thought I'd have a little chat with my Watson. Once we leave the Tower, our relationship as partners will end.”
“Oh, you're right.”
Yuma was surprised to find that he was a bit sad about that. It was a temporary relationship he'd only fomented so he could find someone to frame for the crime, but looking back, the time he'd spent helping her solve The Glass House Murders had been fulfilling.
“If you want, I can help you with investigations again in the future. Well, only when I'm not busy with my work as a doctor.”
“Oh, what a good idea. That is an attractive proposal. I'll have to consider that.”
Tsukiyo didn't sound very interested as she entered the room and made for the couch.
“Apparently I wasn't much use as a partner.”
Yuma gave a bitter laugh at Tsukiyo's cold attitude. Tsukiyo sat down on the couch and went “Eh?”, puzzled.
“No, no, that isn't it at all. You played the role of Watson perfectly. It's no exaggeration to say that it's thanks to you I was able to solve The Glass House Murders. You were a great partner.”
“Thanks,” Yuma said, scratching his nose, embarrassed by the sudden praise. “But you don't seem very keen on letting me continue.”
“Can I change topic, Yuma?”
“I don't mind, but what is it?”
“The Glass House Murders, of course.”
Tsukiyo's double-lidded eyes narrowed. The relaxed atmosphere in the room instantly tensed.
“...What is there to talk about? There are no mysteries left. All the locked room tricks have been solved, and the culprit confessed before committing suicide by taking poison right in front of us.”
Yuma tried desperately to appear calm.
“Yes, that's certainly true. But what was it Mr. Kagami said at the end? He wasn't the one who killed Mr. Kozushima.”
“That was just a lie to assuage his guilt.”
“Really? I think Mr. Kagami planned to kill himself after taking his revenge from the beginning. If the police had come and conducted a thorough investigation, it would have immediately been revealed that he was Mashu Shinju's father. Which would have immediately made it clear that he was the culprit.”
Unable to refute the claim, Yuma remained silent. Tsukiyo continued.
“If he'd intended to die from the start, it's strange that he'd deny only one of the crimes. Especially that one. After all, Mr. Kozushima was the person Mr. Kagami hated the most, the mastermind behind the devil's experiments. Surely if he'd killed him, he would have taken pride in avenging his daughter.”
“...Ms. Aoi, why do you think Mr. Kagami denied killing Mr. Kozushima?”
“The knife...” Tsukiyo said. “The knife that was stuck into Mr. Kozushima's chest when we examined his body. I didn't realize what it meant. But I feel like I've found the answer.”
Confused by the sudden shift in topic, Yuma repeated “The answer?”
“I think Mr. Kagami really didn't kill Mr. Kozushima. Someone poisoned Mr. Kozushima, and he was enraged that he'd been beaten to it. By mutilating the body with a knife, he tried to release some of the anger that threatened to overflow from within him. Mr. Kagami had the master key on the first night, so he could have done it easily.”
“But that's just a possibility. He might have been dissatisfied by what an impersonal murder the poisoning was, and stabbed the body because he was frustrated about that.”
Yuma knew he was rambling. Tsukiyo scratched at her head.
“Yes, that is possible. But Yuma, I've been going back over The Glass House Murders the past few hours, and you see, I've found something... Evidence that Mr. Kagami didn't kill Mr. Kozushima.”
The temperature in the room was suddenly below freezing. Yuma clenched his jaw to keep his teeth from chattering, and forced out a voice.
“Evidence...?”
“I said before that in the first incident, after poisoning Mr. Kozushima, the culprit hid in their room, let us pass as we went up the stairs, then met up with us.”
“Yes, you did say that...”
“But Mr. Kagami couldn't have done that. Because Mr. Kagami was staying in the Second room.”
Yuma felt a shock like a blow to the head. His vision went white.
“Yes, the stairway was too narrow for everyone to gather in front of the First room, so they formed a line on the stairs. The line reached the Second room. If Mr. Kagami had emerged from the Second room, we would have seen him.”
“...Everyone rushed into the First room, and he joined us there.”
“No, that isn't it. At that time, Mr. Kagami was the first person to approach the body and assume control of the situation. That's only possible if he joined the group before we entered the room. In other words...”
Tsukiyo seductively licked her lips. Yuma thought she looked like a snake tasting the air.
“The culprit who poisoned Mr. Kozushima wasn't Mr. Kagami. He was telling the truth.”
“Then, who could have poisoned Mr. Kozushima...”
Feeling dizzy, Yuma forced himself to speak.
“Yes, who indeed? That is the question. But...”
Tsukiyo tapped her temple.
“I don't need all my little grey cells to answer that. It's obvious.”
Tsukiyo's eyes were fixed on Yuma. Like a small animal pinned beneath a predator, Yuma was paralyzed.
“If Mr. Kagami didn't poison Mr. Kozushima, it's odd that he had the poison. Thinking back, when he took the pill case out of his suit pocket, Mr. Kagami looked surprised. The only conclusion is that the real culprit of Mr. Kozushima's murder slipped the poison into Mr. Kagami's pocket to try and frame him for the crime.”
She'd completely seen through him. He had to cover it up somehow, he had to let her know he wasn't the culprit.
“That's true, but... But even if that's true... I don't see how we can tell when that pill case wound up in his pocket...”
His tongue was tied and he couldn't speak properly. His emotions were going out of control and his head wouldn't stay upright.
“Yuma, I do know.”
Tsukiyo whispered.
“While he was listening to my theory, Mr. Kagami had both hands in his pockets.”
The whole room shook. Yuma had to frantically grab at the back of the couch to keep from falling over.
“Are you okay, Yuma?”
Tsukiyo stood up and put her hand on his shoulder. Yuma reflexively tried to back away.
“Well, if you can do that, you're probably fine. Well then, let's continue. The pill case couldn't have been planted in Mr. Kagami's pocket beforehand, because he would have noticed. Since he didn't, we can conclude the pill case was forced on Mr. Kagami after I finished my deduction.”
“But... I didn't have any opportunity to give him the pill case...”
Feeling a sense of despair so strong it made him nauseous, Yuma tried to resist.
“Yes, you did, Yuma. You already know what I'm going to say. It was when you and Mr. Sakaizumi tried to hold down Mr. Kagami. At that time, the pill case containing the poison that took Mr. Kozushima's life was moved to Mr. Kagami's suit pocket.”
There was no more room to argue. Yuma just sat, stunned.
“Looking at the situation, the two who jumped on Mr. Kagami were the only ones who could have snuck the pill case into his pocket. However, Mr. Sakaizumi has an alibi for the first incident, Mr. Kozushima's poisoning. That leaves only one person...”
Tsukiyo pointed her finger at Yuma's nose. She was smiling, but her eyes were full of sadness.
“It's you, Yuma. You're the real culprit behind Mr. Kozushima's murder.”
Yuma had the illusion he'd been thrown through the air. He desperately tried to force his brain to work despite the sparks flying. How could he escape? How could he avoid being tried as a murderer? Yuma's fists unconsciously clenched.
The only person on Earth who knew he'd killed Kozushima was the great detective standing before him. If he could silence her...
Yuma looked straight at Tsukiyo. Tsukiyo met his gaze.
Their eyes met. Yuma's fists fell back open.
There was no way he could do that. Even if he killed Tsukiyo here, the police would arrive in only a few hours. They would perform a thorough investigation and catch him at once.
Besides... However brief it had been, they had worked together to solve The Glass House Murders. They were partners. He couldn't hurt his partner.
Yuma exhaled deeply, as if trying to clear out the dregs that had accumulated at the bottom of his lungs.
“You're right. I killed Mr. Kozushima.”
The moment he uttered the words, his body felt lighter. It was as though the cross he'd been carrying ever since he'd given Kozushima that capsule had vanished all at once.
“I see,” Tsukiyo muttered.
“Do I have to tell you why?”
“Yes. I prefer whodunits solved by howdunits to ones where you have to guess the motive. But if I did have to guess, you said that you left the hospital you worked for to care for your family. I heard Mr. Kozushima had filed a lawsuit to stop the distribution of various treatments on the grounds of patent infringement. I think your family needed one of those treatments. So you killed Mr. Kozushima to stop the lawsuit. Well, this isn't a deduction. It's just a guess.”
As expected of a great detective, even her guesses were dead on. Yuma gave an ironic smile.
“You're right. My sister has ALS.”
“I'm sorry. Well, I can understand your actions. But I can't let what you did remain a secret. It's the job of a great detective to reveal the whole truth.”
“Yeah. I know.”
“You're being quite understanding. I thought for sure you would try to kill me to keep my mouth shut.”
“Even though we were partners, you don't trust me. Do you really think I could do something like that?”
“Yes, you could.” Tsukiyo's eyes darkened. “Humans are capable of using any cruel means to achieve their goals. I understand that better than anyone.”
How much had the great detective seen of the darkness that lurked within the human heart? Yuma felt down his spine as Tsukiyo slowly made her way to the exit.
“Besides, we were never partners. The moment either of us tells a lie, the relationship is doomed. That's why I took out an insurance policy in case you attacked me.”
“Insurance?”
When Yuma asked, Tsukiyo opened the door. On the other side stood Kuruma, Sakyo, Sakaizumi, and Yumeyomi. They wore a variety of emotions: fear, pity, confusion...
“I asked them to wait outside so they could run in and help if they heard any sound of a struggle. Of course, all four of you had your ears to the door and heard our conversation. Isn't that right, Mr. Kuruma?”
Encouraged, Kuruma stepped into the room.
“Yuma, there are many parts of your situation I sympathize with. If our positions were reversed, I might have done the same thing. But the fact remains that you killed someone. In order to ensure our own safety, we need to detain you until the police arrive this evening.”
“...I see. That's reasonable.”
Yuma nodded.
“After discussing it, we've decided to have you detained in the display room. The lock there can't be undone from the inside.”
“I understand. Let's go.”
Yuma dragged his heavy feet towards the door. Yumeyomi let out a small shriek and stepped back.
Just before they passed each other, Yuma called out to Tsukiyo.
“Sorry, Ms. Aoi. Turns out I wasn't Watson. I was Moriarty.”
“Moriarty...?”
Tsukiyo shot him an icy sidelong glare.
“So you're the Napoleon of Crime, are you? All you did was poison Mr. Kozushima and Mr. Kagami.”
Yuma hesitated. Tsukiyo turned around, left the room, and began slowly walking down the stairs. Without even turning back, she spoke in an icy voice.
“You will never take me down the Reichenbach.”