Ma En and Hirota Masami's dinner did not end until nine at night, and that was only the first round. They left the restaurant and wandered the streets for a while, though the conversation no longer touched on the apartment's strange residents or strange events. After that came a night market, oden from a street stall, and karaoke. Hirota Masami drank one and a half bottles of sake at dinner and chased it with two beers at the karaoke bar. By the time they left, she was floating. Even so, they stayed out until nearly midnight before heading back to the apartment.

They said goodnight on the thirteenth floor. Ma En watched Hirota Masami sway through her door into Room 6, and waited until it clicked shut behind her.

Then the hallway went quiet.

Not ordinary quiet. The kind that made even the fluorescent light overhead seem to lose its warmth, bleeding out until it felt thin and clinical. The kind where an ordinary person would become acutely aware of their own footsteps — each one too loud, as if it might disturb something, or as if some other sound were threaded into the rhythm, producing the baseless certainty that someone stood just behind them.

That degree of quiet.

Ma En turned in place and fixed his gaze on Room 5's door. The nameplate slot was blank — every appearance of a unit no one had ever occupied. He'd noticed this when he first moved in. Kamishima Kousuke had explained why Room 4 was cheap, and at the time, not knowing Room 5's situation, Ma En had been satisfied with his arrangement. Now that Hirota Masami had told him what she knew, Room 5 had begun to interest him too.

He wouldn't jump to conclusions simply because of what she'd said. And even if Room 5 did harbor something, he couldn't just break the door down — though he knew he was capable of it.

Just as she'd described: standing in the hallway, he could sense nothing from within Room 5. No presence, no trace of activity. Not the feeling of a unit between tenants, but the deeper stillness of a place where no one had ever been.

He walked toward it. One step. Two steps. His footsteps were soft, but in this silence they sounded almost conspicuous. He reached the nameplate and was about to slide the blank card from its slot when a sound came from the side — a door opening.

His hand froze. He turned.

Room 3 was being pushed open from the inside.

But only a crack.

Someone was watching him through the gap. A single eye, framed by the dark outline of a face barely visible against the blackness behind the door. If Hirota Masami were standing here, Ma En thought, her scalp would be crawling. Even for him — his arm prickled, a charge running under the skin, every hair rising. He wouldn't assume the person behind that crack was something other than human. The strange events in his life had only begun after he'd obtained the Seven Transmutations of the Profound Mystery Records, and Hirota Masami had already told him Room 3 had a long-term tenant.

Logic said: this was a person. Not a monster.

Even if the way he'd appeared was deeply unsettling. For a moment, Ma En almost believed the eye studying him through the crack was the same one that had watched him through his peephole before he'd left — but when he steadied himself and focused, he could feel the differences. They were hard to articulate. Both encounters produced the same breed of grotesque unease, but the texture was subtly, unmistakably different.

"Can I help you?" Ma En spoke first. He was certain a person hid behind that door — probably the clammy, obese tenant Hirota Masami had described.

No answer. The door didn't open further. The eye simply held Ma En's gaze through the gap. It was a gesture of refusal, of withdrawal — and yet the stare pressing against Ma En's body carried something that felt almost like excitement.

"You don't like dealing with strangers?" Ma En kept his voice even. "Is there something you want to say to me?"

The sound came out wet, as if forced through a mouthful of spit. "Hff... hff..." Unmistakably male. It could have been laughter or simply the sound of someone who couldn't catch his breath.

Ma En felt neither drawn nor repelled. Even before the strange events of the past twenty-four hours, his years of chasing the bizarre had introduced him to plenty of people with unusual temperaments. Some were kind. Some were cruel. Some were frightening only because of what their bodies did to them; others were dark all the way down, at the level of personality. Startling encounters happened in any setting. Because Ma En had been through enough of them, he no longer experienced large swings of emotion from a single moment.

"I don't mean you any harm." He opened his hands, palms out, turned his whole body to face Room 3, and took two tentative steps forward. The eye behind the crack didn't flinch. It locked onto his again. Ma En sensed that this eye wanted to tell him something, and so he continued forward.

But one step from Room 3's door, he stopped.

"What's your name?" he asked, and offered his own first: "I'm called Ma En."

"Ma... En?" The voice behind the crack grew slightly clearer, though it stumbled over the sounds — as though the pronunciation sat uncomfortably in the speaker's mouth.

"I moved in yesterday. Room 4." Ma En paused. "Are you coming out?"

No response, but no retreat either. A kind of hovering — drawn forward and holding back at the same time, contradictory impulses stuck in equilibrium. Ma En sensed no malice, but he wasn't going to push any closer. Whatever the man's intentions, Ma En didn't want another confrontation tonight. As long as the other person didn't make the first move, he wouldn't either.

This was conversation. Nothing more.

"Not coming out?" Ma En asked.

"Be careful..." The voice trembled. Before, Ma En hadn't detected fear in it. Now it was there — faint, like dust settling on a surface. "Be careful..."

"Of what?"

"Be careful... Hirota Masami." The words landed, and Ma En pressed the brim of his deep red fedora with two fingers.

"Why?" he asked.

"Hirota Masami... another Hirota Masami..." The voice behind the crack shook as it spoke. "That woman... not that woman..." And then the crack closed — quietly, silently, despite the haste behind the motion. The man clearly did not want to make a sound.

Room 3 fell still.

But the contrast only made Room 5's silence more conspicuous. Room 3's quiet was the quiet of someone holding his breath on the other side of a door. Room 5's quiet was the absence of anyone who had ever existed there at all.

Ma En didn't knock. The man in Room 3 had delivered more questions than answers, but he was clearly terrified — cautious to the point of self-erasure. Ma En had no intention of disturbing that. Years of experience had taught him that rash action triggered chain reactions, and the final link in those chains was rarely something good. The man's caution could be theatrics. It could also be genuine self-preservation.

Room 3's voice made Room 4's legend murkier still. The evening with Hirota Masami had been pleasant — she had a warmth that felt innate rather than performed — but in truth, Ma En's understanding of her remained shallow. Whether she was the one with a problem, or whether the answer lay behind Room 3's door, Ma En wasn't going to chase tonight. He needed rest. He needed to settle in. He needed to bring his own condition up to the standard he'd set for himself before he'd allow himself to step deeper into whatever was unfolding here.

The pursuit of the strange was dangerous. When the danger was immediate, you had no choice — but if there was still room to breathe, Ma En preferred to move at his own pace.

His gaze swept from Room 3 to Room 6, paused on the closed doors of Rooms 1 and 2, then returned to his own door. He inspected the area carefully. No sign that anyone had visited. He opened the door using the method he'd preset, and just before stepping inside, he felt Room 3's door open again behind him — but the person inside still didn't emerge. Still watching.

Ma En slipped inside and shut the door. This time, he heard the Room 3 tenant finally come out. The man's footsteps were hurried, almost frantic, rushing toward the elevator. The sound faded. The hallway sank back into its pale, bloodless quiet.

If strangeness had a density, this floor's had long since become too thick to breathe.

Ma En felt himself being drawn into a vast whirlpool — felt, with a certainty that settled in his bones, that if he didn't escape now, he never would. There would be no standing on the sideline.

This did not trouble him.

He confirmed no one had entered his room while he was gone, reset the security mechanism, and retrieved the Seven Transmutations of the Profound Mystery Records along with his research materials. Compared to the strangeness of this floor — which was beginning to acquire contours, a shape he could almost trace — this wordless book was stranger still. He had a premonition: he needed to extract something from it that he couldn't yet understand, something that might keep him alive in whatever was coming. If the story unfolding around Room 4 truly belonged to a reality his rational mind couldn't account for, then only an equally incomprehensible mystery could serve as a weapon against it.

Then again, Room 4's events might turn out to be ordinary at their core — human-engineered, explainable. In which case, the Seven Transmutations he was trying to decode might be the thing that brought the real horror down on him.

When something could be argued as both beneficial and catastrophic with equal conviction, the moment of decision was always closer than you thought.

Ma En made the choice he wanted — not the one that was theoretically correct.

His approach hadn't changed from previous sessions. He still focused on the flash of intuition that had struck him days ago: the Twenty-Four Solar Terms. Every prior attempt had failed, but tonight, as he stared at the twenty-four strange characters he'd transcribed onto paper and cross-referenced them against his research materials — the ancient wisdom, the codification of natural law that had survived millennia — something began to happen. The characters and the solar terms seemed to be reaching toward each other through a medium he couldn't name.

The deeper the sense of connection grew, the more it felt like it might be an illusion. The shapes of the twenty-four characters — their angles, the direction of every line — seemed to be narrating something. And then, as though his vision were blurring, the structures began to grow more complex. Layer upon layer, until they resembled star charts with intersecting trajectories, each point along every line inscribed with further patterns at a scale too small to see, micro-engravings upon micro-engravings.

The complexity was nauseating. The characters began to rotate — kaleidoscopic, each turn generating a new configuration. Faster, and it was a hundred flowers blooming at once. When the intricacy and the relentless variation crossed some threshold, what had once been beautiful curdled. From within that elegant structure and motion, something twisted and ugly was born. Ma En felt a wave of vertigo crash through him. He couldn't stop himself from falling.

His consciousness could not command his body's convulsions.

His limbs jerked. His eyelids hammered shut and forced themselves open. His organs felt wrung like wet cloth, the pain savage and absolute. Everything in front of him dissolved toward white noise. Before it went completely — before the last image bled away — he could see the foam spilling from the corner of his own mouth.

He saw it happening to himself.

Darkness flooded in. Within the darkness, countless terrors took shape — half-visible, half-imagined — and wound themselves around his soul.

Yes. Ma En could see his own soul. What a thing that was — to look at yourself from the outside, from a vantage point no living person should occupy. He was trembling. He would not deny that what he felt right now was fear, and that it eclipsed every other emotion. Even so, he recognized what was happening. This was the thing he'd been pursuing. It was hurting him, and some part of him was fighting to keep it from doing worse.

The battle was subtle. Blurred. Dark. Hallucinatory. As long as he wanted to persist, it would not stop.

And then — before he lost consciousness — it did.

Like a switch thrown. The agonizing, uncontrollable sensation vanished as though it had never existed. Only the fear lingering in his chest and the foam drying at the corner of his mouth confirmed that what had happened was real.

A strange impulse surged through him. Ma En didn't understand it — but like every flash of intuition before it, the thought that surfaced in his mind was sudden and complete:

Blood sacrifice.

— So that was why the killer had done what he did.

Ma En sat with the impulse. He wiped the foam from his mouth in silence. Half of him remained calm — as if those psychological exercises he'd practiced had actually worked. The strange compulsion could not breach his rationality. What he ought to do right now, he decided, was not sleep. It was, as originally planned, to work through several complex math problems.

Dangers born of study and contemplation might, perhaps, be eased by study and contemplation. He wasn't certain of this. But then, everything happening to him was — just as he'd hoped — exactly the kind of strange and bizarre he'd been looking for.