3
How had things come to this?
Sitting down on the long-piled carpet with his back to the wall of the stairwell, Ichijou Yuma looked up at the sky.
Before he'd realized, the clear sky had been covered by heavy clouds, and a light snow had begun to fall across the transparent glass enclosing the space.
He look at the hands of his watch. It was already after 5:00 P.M. It had been nearly five hours since he'd been locked in the display room.
Kuruma and the others who'd brought him to the display room had only taken the bottle with “Pufferfish Liver” on the label, afraid he would use it to commit suicide, before leaving him.
The cold of the carpet seeped through his trousers and into his hips, chilling him to the bone. Yuma adjusted the collar of the wrinkled old coat he wore to ward off the cold – apparently the same one Peter Falk had worn while filming Columbo – and shrank inwards.
“Where did it all go wrong...?”
The question spilled unconsciously from between his lips.
Was it when he'd approached Kozushima Tarou with murder in his heart? Or was it when he decided to attend the mysterious banquet held at the Glass Tower, thinking it was the perfect opportunity? Or...
“...Was it when I met that great detective?”
The soft words, exhaled with his white breath, melted away into the cold air.
There was no point thinking about it now. Yuma put his head between his knees. It was all over.
This story, The Glass House Murders, had already come to a close.
The truth had been uncovered by the great detective, and he, the culprit, had been arrested.
The bizarre series of locked room murders that had taken place in that glass spire had been solved. There was nothing left for the culprit to do but quietly leave the stage.
Yuma slowly closed his eyes.
The image of the great detective, a cynical smile on her handsome face, was engraved on the backs of his eyelids.
“...Come to think of it...”
A murmur unconsciously came from between his lips. Yuma looked back up.
“What was that code?”
The mysterious code written on the paper stabbed into Kozushima's body by the knife. Tsukiyo hadn't mentioned it a single time since they'd found it.
Maybe she didn't want to acknowledge the code to the others because it would give away that she'd used the master key to examine the bodies last night. Or maybe she didn't think it was particularly relevant and didn't care.
Yuma put his hand on his forehead, thinking.
It must have been Kagami who'd stabbed the knife into Kozushima's body. That being the case, why on Earth had Kagami left behind a code? And what did it say?
“And also, who pushed me down the stairs? And who eavesdropped on us...?”
Yuma's brain, having been given a few hours of rest, was working for the first time in a long while.
The logical assumption would be that Kagami was the one who'd pushed him down the stairs. Kagami would have wanted to know how close Tsukiyo, as a great detective, was to the truth. Kagami was in the Second room, so he could have hidden there until Yuma finished searching the display room and gone back down, then left the room and attacked him from behind. But...
“But what did Kagami have to gain from pushing me down the stairs?”
His thoughts hitched. He'd overlooked something important. The premonition set his whole body on edge.
Yuma suddenly looked up. His face scrunched up. Something was sparkling on top of the bookshelf full of Western mystery novels across from him. Yuma stood up, drawn to the shelf like a moth to a flame.
It was a conical piece of glass. An object in the shape of a TRIDENT, the revolutionary medical instrument developed by Kozushima, sitting on top of a thick overturned book.
“This should have been on the desk in the First room... Why is it here?”
Yuma picked up the object. A DNA double helix was floating in the oil that filled the cone. The next moment, a memory from three days ago came back to him.
–– I did have this tower made as a perfect replica of the TRIDENT, down to the tiniest detail.
“A perfect reproduction... DNA...”
Yuma looked up at the sky and talked to himself as the object fell from his hand. The glass cone shattered across the floor, but Yuma paid it no mind as he dropped to his hands and knees.
Kozushima was a perfectionist with an abnormally strong ego. There was no way he would compromise on the design of the Glass Tower, modeled after his greatest achievement, the TRIDENT.
Yuma clenched his fist and pounded on the carpet. The shards of glass pierced his hand, slicing through it, but he didn't care. He slammed his fist against the carpet again and again as he made his way towards the stairwell. Heavy, muffled bangs echoed through the glass cone.
“Considering the Tower's structure, it must be somewhere around here...”
When he hit one particular area of carpet next to the stairwell, a sound obviously different from the others, like the rattle of a blow to an empty oil drum, reached his ears.
That was it! Yuma grabbed the carpet with his bloody hands and pulled. A square meter of carpet that reached the wall of the stairwell flipped up, exposing a metal trap door.
“There was never going to be only one spiral staircase... DNA is a double helix.”
Yuma muttered between heavy breaths.
“The only way it could be a 'perfect replica' is if there were two staircases.”
Yuma was on the outermost edges of a bigger mystery, one even that great detective couldn't solve. Feeling his body temperature rising, Yuma grabbed the handle and tried to open the door. But the door was embedded in solid concrete and wouldn't budge. Yuma let go of the handle and looked closely at the door. There was an LCD keypad with three small squares lined up above a numeric keypad.
“A password!”
He'd gone to such lengths to find the hidden door, and now he couldn't open it. Yuma furiously scratched at his head for a few seconds, then gasped.
“The code!”
Yes, the code. The incomprehensible code written on the paper pinned to Kozushima's body. Perhaps it was related to the hidden door.
Yuma took his smartphone out of his jacket pocket and looked at the picture of the code he'd taken last night. The blood on his fingertips got on the screen, but he couldn't worry about that now.
Yuma's eyes opened wide and he stared at the code without even blinking.
“It really does look like the cipher from The Adventure of the Dancing Men. But that cipher used many different types of figures, while there aren't that many here... only four types. I can't solve this using the same method as the code of the Dancing Men.”
Muttering to himself, Yuma zoomed in the image.
“There's a space every three men, does that mean that each set of three represents one letter? Since 'O', 'U',' and 'B' are each written out as a single letter, that seems likely. So, three men represent one letter of the English alphabet...? But why didn't they just write 'O', 'U', and 'B' in the code?'
Yuma put a hand to his mouth.
“It isn't that they 'didn't', but they 'couldn't'? Is there a limit to how many letters can be written with three dancing men?”
He felt like insects were crawling across the surface of his brain. His subconscious had picked up on something, but he couldn't tell what. He bit his lip in frustration.
“Three men represent one letter... there are only four types of men... there are letters that can't be expressed in the code...”
Suddenly, out of the corner of his eye, he saw the thick book lying on top of the bookshelf. The spine read “General Theory of Genetic Engineering.”
The display room was meant to contain nothing but Kozushima's collection of mystery paraphernalia. A specialized book on genetic engineering being there meant that someone had brought it there, probably from the First room alongside the model TRIDENT.
“Who would do something like that, and why...?”
After giving it some thought, Yuma shook his head. What was important right now was that that book was almost certainly a clue to the mystery behind the Tower itself.
“Genes... genes...”
Yuma repeated to himself until, finally, a flash of inspiration ran through his head.
“DNA!”
Yuma's voice pitched far upwards as he looked back to his smartphone.
“DNA is made up of four bases: adenine, or A, guanine, G, cytosine, C, and thymine, T. A combination of three bases forms one of the twenty amino acids! And combining those amino acids creates all sorts of proteins!”
Yuma ran over to the bookshelf and picked up General Theory of Genetic Engineering, frantically flipping through the pages.
“Each of the twenty amino acids is assigned a letter from the alphabet. So if we apply that...”
Yuma opened to the page listing the amino acids corresponding to each combination of three bases, alongside their alphabetical labels listed in a table. Then he went back to the stairs and put the book and his smartphone down on the carpet.
“First, the three men on the top row. Seeing as how the top and bottom rows only have one set of three, it seems more likely they mean 'beginning' and 'end' rather than representing letters. In that case...”
Yuma touched his fingertips to the blood oozing from his lacerated palm, and wrote 'ATG', the DNA code representing the start codon of a transcript, on the concrete wall of the stairwell. The start codon was what represented the beginning of a DNA code, a message that read “read the base sequence after here and produce the indicated protein”.
“If this is correct, then the man raising his right hand – right hand? Is he facing me or turned away? The man raising his right hand is 'A', the one raising both hands is 'T', and the one doing a headstand is 'G', which means by process of elimination that the remaining man, the one raising his right leg, in 'C'. In that case...”
Alternating looks between the smartphone in his hand and the book on the carpet, Yuma wrote on the wall in blood.
“The second line begins with ACA, which corresponds to the amino acid threonine. The abbreviation for threonine is 'T'. Next is CAC, which is histidine, 'H'.”
After carefully deciphering each set of three, Yuma had written “THINK” on the wall in blood.
THINK... It was a word. His method was correct.
“Hmm? The next one is 'TGA'. That doesn't correspond to an amino acid. Does 'no answer' symbolize a space? Well, it's at the end of the line, so it's fine. Then the third line...”
One after another, DNA codes and their corresponding letters were written in blood on the concrete. A few minutes later, Yuma had written up to 'TGG', the DNA codon for 'end of translation', and stared at the answer he'd come to.
THINK OF A NUMBER
“Think of a number...”
Yuma frowned. He had tried so hard to solve the complicated code, but the message he'd found was far from what he'd expected.
“Think of a number? I solved this code so you'd tell me the number!”
Yuma punched the wall of the stairwell in a fit of rage. A numbing pain ran through his knuckles all the way to his head. Yuma grit his teeth and held his hand.
Why was such a complicated code used to write a message as meaningless as “think of a number?” Anger diluted in pain, Yuma took a deep breath.
There must have been some hidden trick behind the message. Yuma inhaled, exhaled, inhaled again, staring at the message written in blood.
“Think of a number... The screen above the keypad has three spaces... but it only says to think of one number. A singular number...”
The moment he said that, his whole body shook as though he'd been struck by lightning.
“Think of a number!”
Yuma screamed and ran to the bookshelf where the TRIDENT had been, running his finger along the spines of the foreign books.
The moment he reached the bottom shelf, his fingers stopped. The spine he was touching read “Think of a Number”.
“This is it...”
Fingers trembling, Yuma took the book off the shelf.
Think of a Number. A mystery novel by American author John Verdon. A man receives a small envelope alongside a letter which reads “Think of any number up to a thousand.” When the recipient opens the small envelope, it contains a piece of paper with the exact number he'd thought of written down.
The story begins with the unique puzzle of “a letter that can read the recipient's thoughts”, and eventually develops into a series of murders. Various mysteries reminiscent of classic honkaku are presented, and the work had received high praise among mystery enthusiasts.
“Originally published in 2010...”
Yuma opened the book and checked the year of publication. No matter how good a book it was, such a recent release didn't seem like the sort of thing that belonged in the Kozushima Collection. Which meant it was safe to assume that this copy was brought to the display room alongside the model of the TRIDENT.
Yuma flipped through the book, unconcerned with the bloodstains he left on the pages.
“The number he thought of was...”
Yuma's fingers stopped. His eye had landed on the number he was looking for. The number the character in the story had thought of:
“Six five eight!”
He shouted, then ran back to the trapdoor and input the number on the keypad. Once “658” was being displayed on the LCD screen, Yuma hit enter, praying he was right.
The sound of metal on metal filled the air. Yuma gently reached out and grabbed the handle. The door which had refused to budge earlier began to rise. Underneath was a glass staircase.
Pumping his fist, Yuma tied a handkerchief around his injured hand as an improvised bandage, then began to descend the hidden stairway.
It was made almost identically to the regular stairs descending from the stairwell. It was a spiral staircase, just wide enough for two people to walk shoulder to shoulder. The walls and ceiling were black glass, and the whole thing was softly lit by LEDs embedded in the walls.
Just like a strand of DNA, this staircase probably formed a double helix together with the regular stairs. Surely, the regular staircase was just on the opposite side of that wall. When the thought occurred to him, Yuma stopped in his tracks.
Was this hidden stairway the reason Yumeyomi had been so insistent that there was an evil presence lurking in the Tower? Yuma didn't believe she had genuine supernatural powers, but if she was able to make a living as a psychic, she may have had keener senses than the average person. Perhaps she had been able to hear footsteps going up and down these stairs, on the other side of the wall, causing the illusion of a spiritual presence wandering the halls.
Come to think of it, on the first night, when he'd been returning to his room, he'd thought he heard faint footsteps behind him and been afraid someone was following him. That may have also been coming from the hidden stairway.
Who could have been using the hidden stairs at that time? Could it have been the person who'd escaped from the dungeon? No, they'd concluded that person probably didn't exist. Then who could it have been...?
Feeling his head ache, Yuma started moving again. After descending one and a quarter rotations around the spiral, he came to a small landing with a passageway.
“One and a quarter rotations, this should be the height of the First room...”
Yuma peered into the dark, unlit passageway. It was narrow, bare concrete. He would have hit his head if he'd stood straight up. It was about three meters long, and at the end of the passageway was what looked like an ovular window set in the wall. Cautiously, Yuma entered the passageway.
He went to the end, peered into the oval window recessed in the wall, and exclaimed “Huh?”
Through it, he could see the First room. The model of the Glass Tower lying on the floor, the mahogany desk, and the body of Kozushima, knife in his chest, were all there.
What did it mean? What was going on? Confused, Yuma desperately tried to remember the layout of the First room. If he could see Kozushima's body from that position...
“A mirror... a one-way mirror.”
A weak voice escaped Yuma's throat. That was right, there was a mirror hanging right where he was. It wasn't an ordinary mirror, but a one-way mirror, through which it was possible to observe the room from the hidden stairway.
But why had it been designed that way...? Yuma's brain was beginning to heat up from the amount of new information forcing its way in. Holding it, he looked down, where he saw something beneath the one-way mirror.
“A door?”
Yuma knelt down and squinted. There, next to a handle, were three small square LCD displays and a keypad. It looked exactly like the hidden door in the display room.
Yuma swallowed and pressed the keys “6”, “5”, “8”, and “enter”. There was a faint clang, and Yuma grabbed the handle and pushed. A door of about one meter smoothly slid open. Yuma got down on all fours and crawled through the door into the First room.
“...What is going on?”
Trapped in a whirlwind of confusion, he stood up and turned back to check the door. Beneath the mirror was a waist-high bookshelf, and the moment he saw that was what opened into the room, Yuma's face tensed.
A mirror at face height, directly above a low bookshelf. The exact same layout existed in the Fourth room – his room. The memory of the first night came back to him in a numbing rush.
That night, when he'd returned to the Fourth room and looked in the mirror, he'd felt like somebody was watching him. At the time, he'd assumed that it was an illusion caused by his guilt over killing Kozushima, but perhaps he was wrong.
“...Was somebody watching me?”
Feeling like ice water had been poured on his head, Yuma shuddered.
The Fourth room was designed so that it could be observed and entered at any time via the hidden staircase. No, it wasn't just the Fourth room; the Fifth and Sixth rooms had also had similar arrangements of mirrors and bookshelves. Most likely, all the rooms in the Glass Tower were designed the same way.
“In that case... In that case, the locked room tricks are meaningless...”
Yuma muttered, his voice heavy. In fictional locked room mysteries, secret passages are a sort of taboo. Introducing a secret passage as the solution to to locked room mystery would be boring.
And, in fact, Tsukiyo hadn't even considered the possibility of a secret passage, either.
“So was Ms. Aoi's deduction wrong...?”
After thinking about it for a few seconds, Yuma shook his head. No, given the structure of the Tower, the only rooms with secret doors and one-way mirrors were the First through Tenth rooms, which were right against the central pillar. The secret passage couldn't be the answer to the second incident, which took place in the dining room.
And besides which, Yuma had committed the first murder himself, and Kagami had confessed to the other two. The three locked room tricks Tsukiyo had presented as the solution to The Glass House Murders should have been correct.
So did that mean this hidden stairway had no connection to the incident?
No, that wasn't it. It couldn't be. Yuma clenched his fist.
There was no doubt that someone had been observing him using that hidden stairway. There was no way that person wasn't involved in the tragedy that had taken place in the Tower. His intuition wouldn't budge on that point.
Just a little more. Yuma could feel that he was right on the verge of something.
He could see the outline of something hideous, squirming within the Tower, and that he couldn't make out what it was was so frustrating that he clutched his head until his fingernails drew blood. The sharp, focusing pain cooled his boiling brain somewhat.
“Let's check the rest of the staircase first.”
Yuma took a deep breath and walked back down the passageway, then descended the spiral staircase. Just as he'd imagined, there was another passageway at the height of each guest room, each ending with a window and a door. Once he'd passed the passage to the Tenth room, he didn't pass any more. Two and a half rotations down, the stairs ended at a door. He had probably passed the first floor and descended to the basement.
Yuma found the keypad and entered “658”. The automatic door slid to the side, producing a heavy mechanical sound.
He cautiously exited the room. There were several large generators standing in a row.
“The power room... this is where it ends.”
The automatic door silently slid closed behind him, leaving nothing but a soot-stained wall. On the other side of the generators, he could see an empty shelf and the door to the storeroom.
Yuma looked down and saw a numeric keypad embedded in the floor, hidden in the shadow of a generator. He typed in “658”, and the hidden door slid back open without a sound.
“No one would go out of their way to go to this side of the generators, so I suppose this is the perfect hiding spot.”
So the question was, what now? Yuma crossed his arms. He'd managed to escape from the display room. He could probably go outside. But what would happen then?
His car had flat tires, and walking down that snowy mountain would be suicide. Besides, everyone already knew that he was the culprit behind Kozushima's murder. Even if he did manage a miraculous descent down the mountain, he'd immediately be placed on the wanted list. He'd never be able to escape.
And also... He had made up his mind to atone for the crime he'd committed. There was no point shaming himself by struggling now.
So shouldn't he just quietly return to the display room and wait for the police?
“That's not right, is it?” Yuma asked himself.
Surely, The Glass House Murders hid a deeper, darker secret than what the great detective Aoi Tsukiyo had uncovered. He had managed to grab hold of the very tip of the beast's tail.
For the past four days of tragedy, he had played the roles of Watson and of culprit. It wouldn't be bad to experience how it felt to be a great detective for a few moments before the end.
Yuma pressed the keypad on the floor and opened the door, went inside, and sat down on the stairs. The door closed. Now he could think without any risk of being disturbed.
So, where to start? Yuma clasped his hands, and suddenly noticed some sort of stain on the corner of the stairs. He brought his face in closer.
“...Blood?”
He frowned and furrowed his brow. Looking closely, it was definitely a bloodstain.
Was it from his hand? Yuma gently touched the bloodstain. His fingers came back bone dry.
“It's dry... It isn't my blood.”
If it had hardened that much, it had to be at least a full day old. What could have happened there on the hidden stairway?
An ominous feeling sucked all the moisture from his mouth.
“Breathe. Just stay calm.”
Yuma told himself as he closed his eyes and collected his thoughts.
There was no doubt that someone had been using these stairs during the four days The Glass House Murders had taken place. The footsteps he'd heard on the first night had likely come from someone moving up the hidden stairway. And thinking back, Yumeyomi had said on the morning of the second day that she'd sensed something ominous in the Tower.
“So, the person only started to move after I killed Kozushima on the first night.”
Yuma closed his eyes and thought out loud.
The question was who they were. It wasn't likely it was someone he didn't know. He hadn't passed them going down the stairs earlier. That meant it was someone who occasionally left the hidden stairway. That being the case, it was unlikely the person would have managed to avoid the eyes of so many people over the course of four days.
Besides, it was beyond question that Kozushima had been the one to design the hidden stairway. It was hard to imagine such an elusive man would have told an outsider the code to open the door. Aside from Kozushima, the only people who might have known about the existence of the hidden stairs were Oita and Madoka, his live-in servants. It was especially likely that Oita knew, having served Kozushima faithfully for so long.
But if that was the case, why hadn't Oita mentioned the existence of the hidden stairway, despite the unusual circumstances of his master's murder?
Because he knew no one was there. So had it been Oita who'd been using it? No, even after Oita was killed, Yumeyomi had continued to rant and rave about the evil presence.
So who had could have used the hidden stairway?
Who had been watching him through the one-way mirror on the first night?
Kozushima Tarou, Kuruma Koushin, Kagami Tsuyoshi, Oita Shinzo, Tomoe Madoka, Sakyo Kousuke, Yumeyomi Suishou, Sakaizumi Taiki, Aoi Tsukiyo...
The faces of everyone involved in the case floated across his mind.
Of them, who had the chance to use the hidden stairs on the first night...?
When he asked himself that, it felt like an explosion in the center of his brain. Yuma's eyes shot open and he clapped his hands over his face.
“No... No, that's not possible...”
Yuma was breathing heavily. His heart raced as memories of the past four days flashed across his vision in a slideshow.
Placing one hand on his chest, where his heart was pounding painfully hard, Yuma stared off into space with his mouth half-open.
His synapses were firing so quickly they threatened to overload, electrical signals consolidating into a theory. A theory that was beyond imagination.
“Is that even possible...?”
Yuma asked, voice a strangled rasp. He shot back to his feet, sprinting up the glass stairs. He ran out of breath well before he arrived and felt his thigh muscles strain, but he ignored his body's protests and kept moving his legs.
Just as his lungs began to ache and his legs began to reject his commands, he reached his destination, the passageway to the First room.
Gasping for air, Yuma staggered down the passage, entered the passcode to open the door, and dragged himself up to Kozushima's body.
Taking several seconds to catch his breath, he watched Kozushima staring off into space with clouded eyes. Wincing at the cold, rubbery feeling of his dead skin, Yuma grabbed him by the wrist and lifted. The stiff joins of his elbow and shoulder creaked, and Kozushima's whole body rose off the ground.
Yuma grit his teeth until they groaned, and let go. Gravity brought Kozushima back to the floor, and Yuma fell with him down to his knees.
“Oh my God... This is absurd...”
His voice leaked from between his clenched teeth.
His theory was confirmed. It truly was beyond imagination.
It was such an abnormal idea his instincts rebelled against it. Something hot and nauseous rushed up his esophagus. Yuma turned away from the body and gagged. Sticky yellow acid fell from his mouth to the floor. An agonizing bitterness was left behind, filling his head.
But this was the truth. Everything he'd seen and heard in the past four days supported it.
Yuma stood up and went to the bathroom to rinse his mouth. He roughly wiped with the sleeve of his jacket and stared into the mirror.
“Calm down. Think about it the other way around. Now, everything is solved,” the man in the mirror told him.
“I've arrived at the truth. The real truth of the tragedy that took place in the Glass Tower. All that's left now is to decide what to do with it.”
Staring into the mirror, Yuma thought about his plan.
He had to tell the people in the Tower the truth he'd arrived at. But that would be difficult.
Thanks to the hidden stairway, it would be easy for him to escape from the display room and talk to the others. But he doubted even Kuruma would be willing to listen to a man being held as a murderer.
He had no choice but to be a bit forceful. But he was drastically outnumbered. In order to get them to listen to him...
“...Oh.”
Yuma turned and left the bathroom, then climbed the hidden stairway back to the display room. The glass case containing the shotgun from Laura. Yuma slowly typed “6” “5” “8” “enter”, and the sound of the lock undoing echoed off the walls.
Yuma set his lips in a grim mask and opened the reinforced glass door, taking the gun and ammo from within.
He was hesitant to threaten the others, but this was the only way he could get them to listen. All that was left was to convince them of the bizarre truth he had discovered.
Solving the mystery was difficult, but convincing others of the truth was equally difficult. That was the sort of thing Yuma never would have understood unless he'd tried to play the role of the great detective.
“Come to think of it, I guess this is the part where the great detective is supposed to say 'that'. I might as well take the opportunity to act cool.”
With a dissonant smile, Yuma savored the feeling of the speech on his tongue.
“A challenge to the reader. With the new information in your possession, it will be much easier for you to deduce the truth behind the tragedies that took place here in the Glass Tower. What really happened here over the past four days? I want you to be the one to uncover that. This is my challenge to the reader. I wish you good deductions, and good luck.”