在一座位於城市邊緣的老舊工業區裡，有一棟灰暗而高聳的工業大廈。這棟大廈雖然外觀陳舊，但內部卻依舊有不少公司在此運作。阿成是一名保安，負責大廈的夜間巡邏工作。他已經在這裡工作了五年，對這裡的一切都了如指掌。
工業大廈的燈光總是有規律地熄滅，只有走廊的幾盞燈會保持亮著，以便值夜班的人員安全通行。然而，十二樓卻是個例外。這一層的燈光從未熄滅，不論是深夜還是清晨，總是亮如白晝。
剛開始，阿成並沒有多想。他以為可能是某家公司加班或忘記關燈。但隨著時間的推移，他發現這種現象並非偶然，因為五年來，十二樓的燈光從未變化過。更奇怪的是，當他查詢大廈的租戶名單時，發現十二樓竟然沒有任何公司登記，也沒有租賃記錄。
管理處的人對此事也語焉不詳，他們只說：「十二樓早就沒人租了，那層樓是空的。」這樣的回答讓阿成心裡泛起了陣陣不安，但他知道自己只是個保安，沒必要多管閒事。
某天深夜，大約凌晨一點，阿成像往常一樣進行巡樓。他搭乘升降機逐層檢查，當升降機抵達十二樓時，門緩緩打開。一陣刺眼的白光從門縫中洩出，讓他不由自主地眯起了眼睛。走廊裡異常乾淨，地板閃閃發亮，牆壁潔白如新。這與工業大廈其他樓層的破舊形成了強烈的對比。
阿成小心翼翼地踏出升降機，他的鞋底與地板碰撞發出的聲音在空蕩蕩的走廊中回蕩。整層樓靜悄悄的，只有走廊盡頭的一扇虛掩的門內傳來清晰的鍵盤敲擊聲，「啪、啪、啪」，節奏穩定而沉著。
他站在門口，猶豫了一下後試探性地喊了一聲：「保安巡樓，有人在嗎？」然而，門內的鍵盤聲依舊沒有停止，也沒有任何人回應。
阿成感到一股莫名的寒意從腳底升起。他想了想，最終還是選擇退回升降機。他按下關門鍵，心跳卻不由自主地加快。當升降機門關上後，他感覺到背後彷彿有什麼東西在注視著他，但當他轉身看向閉路電視螢幕時，十二樓的畫面卻是一片漆黑。
「怎麼可能？」阿成喃喃自語。他明明剛才親眼看到十二樓亮如白晝，可監視畫面卻顯示那裡一片漆黑。他低頭看了一眼手錶，時間顯示為凌晨一點二十三分。他心裡湧上一股說不出的不安，但又無法解釋這一切。
隔天，他忍不住向管理處再次提起十二樓的問題。然而管理人員翻查了許久資料後，只是重複著相同的答案：「十二樓早就空置了，那層樓根本沒人。」
阿成知道再問下去也不會有結果，他選擇保持沉默。但那晚，他的心情仍然無法平靜。到了夜裡，他再次開始巡樓。然而這一次，當升降機到達十一樓時，顯示板突然閃了一下，直接跳過了十二樓，停在了十三樓。
阿成按下按鈕試圖返回十二樓，但無論如何操作，升降機都無法停留在那一層。彷彿整個系統被人為設定，完全屏蔽了十二樓。
他無奈地返回更亭，再次查看閉路電視。螢幕上的十二樓仍然一片漆黑，但他知道，那層樓的燈光依然亮著，只是現在已經不再允許任何人踏足。
接下來的幾天，他發現每當升降機經過十二樓時，都會自動跳過。而且，自從那晚之後，他再也沒聽到過那扇門內傳來的鍵盤聲。但阿成心裡總覺得，那層樓並非真的空無一人。
有一天深夜，他夢見自己再度站在那扇虛掩的門前。門內傳來低語聲，像是有人在討論什麼。當他試圖推開門時，一隻冰冷的手突然抓住了他的手腕。他驚醒過來，全身冷汗直冒。
從那之後，他開始注意到一些奇怪的現象。每當他經過十二樓所在的位置時，就會感到頭皮發麻，心跳加速。有幾次，他甚至聽到有人低聲呼喚他的名字，那聲音低沉沙啞，如同從地底傳來。
有一天，一位新來的大廈租戶聽說了十二樓的事情後，好奇地向阿成打聽：「聽說這棟大廈以前發生過什麼事，是不是真的？」
阿成愣了一下，問對方從哪裡聽來這些話。對方支支吾吾了一會兒才說：「之前聽別人提起，好像有什麼火災還是事故發生過……」
火災？事故？阿成心頭一震。他回憶起自己剛來這裡工作時，好像隱約聽說過一些關於這棟大廈過去的傳聞。但那些傳聞都模糊不清，只提到曾經有一場大火奪走了不少人的性命，而火災似乎就發生在十二樓。
這個念頭讓他更加確信，那層樓絕非普通空置樓層。它存在於那裡，也許並不是為了人類，而是為了某種更高層次的秩序。
從那以後，阿成不再試圖接近十二樓。他知道有些秘密是不能觸碰的，有些真相也許永遠不該揭開。而那層始終亮著燈光的十二樓，就像是一個無聲的警告，提醒著所有人：有些事情，不該被打擾，有些地方，不該被闖入。
夜深人靜時，大廈依舊矗立在工業區中。十二樓的燈光明亮刺眼，但卻沒有人知道，它究竟是在為誰而亮著，又或者，它究竟是在守護什麼。
English Version
In an aging industrial district on the edge of the city stood a tall, grey building whose worn exterior gave little indication that it still housed a number of active businesses within, and among the few who knew its rhythms intimately was Ah Shing, a night security guard who had spent five years patrolling its corridors, becoming so familiar with its patterns that even the smallest irregularity would not escape his notice, which is why the twelfth floor unsettled him in a way he could not easily dismiss unlike the rest of the building, where lights were systematically switched off after hours leaving only essential corridor lighting for safety, the twelfth floor remained perpetually illuminated, its brightness constant regardless of the time of night or day, and at first he assumed it was the result of overtime work or simple negligence, but as weeks turned into months and months into years, he realized that the lights on that floor never changed, not once in all his time there, and what made it even stranger was that according to the building’s tenant records, there were no registered companies occupying that floor, no leases, no official activity, and when he asked management about it, their answers were vague and dismissive, insisting that the twelfth floor had long been vacant, a statement that only deepened his unease rather than resolving it; one night, at around one in the morning, during his routine patrol, he took the elevator as usual, moving from floor to floor to ensure everything was in order, and when the elevator doors opened on the twelfth floor, a blinding white light spilled into the cabin, forcing him to narrow his eyes as he stepped out into a space that felt entirely different from the rest of the building, the corridor unnaturally clean, the floor gleaming as though newly polished, the walls pristine and untouched by the decay visible elsewhere, and the silence was absolute, broken only by the steady, rhythmic sound of typing coming from a half-open door at the far end of the hallway, each keystroke echoing sharply in the stillness as if it were the only sound that existed in that moment; he approached cautiously, his footsteps reverberating louder than expected, and when he reached the door, he called out, announcing his presence as part of his patrol, yet the typing did not stop, nor did anyone respond, and as he stood there, a cold sensation crept up from his feet, spreading through his body with a quiet insistence that told him something was not right, and after a brief hesitation, he chose not to enter, instead retreating back to the elevator, his heart beating faster than usual, and as the doors closed, he felt an unmistakable sensation that something behind him was watching, observing him silently from the bright corridor he had just left; once back at the security station, he immediately checked the surveillance monitors, expecting to see the brightly lit twelfth floor, but what appeared on the screen contradicted everything he had just witnessed—the feed showed only darkness, the entire floor unlit and empty, as though it had never been illuminated at all, and he stared at the screen in disbelief, glancing at his watch to confirm the time, which read 1:23 a.m., grounding him in reality even as his experience seemed to defy it; the following day, unable to shake the incident, he questioned management again, hoping for a clearer explanation, but they repeated the same answer, insisting that the floor had been vacant for years, offering no further details, and realizing that he would gain nothing more from them, he kept his concerns to himself, though his sense of unease lingered; that night, when he resumed his patrol, something had changed—the elevator, which had previously stopped at every floor, now skipped the twelfth entirely, moving directly from eleven to thirteen as if the floor in between no longer existed, and no matter how many times he pressed the button, it refused to stop there, as though the system itself had been altered to prevent access, and when he returned to the security room and checked the cameras again, the twelfth floor remained shrouded in darkness on the monitors, yet he could not forget the brightness he had seen with his own eyes, nor the sound of typing that had echoed through the corridor; in the days that followed, the pattern persisted, the elevator bypassing the twelfth floor without exception, and the strange phenomena gradually shifting from external events to something more personal, more invasive, as he began to experience unsettling dreams in which he stood once again before that half-open door, hearing low murmurs from within as though multiple voices were engaged in conversation, and when he tried to push the door open, a cold hand would seize his wrist, pulling him back abruptly, causing him to wake in a cold sweat, his heart racing as the remnants of the dream clung to him with disturbing clarity; even during his waking hours, the influence of the twelfth floor did not fully recede, manifesting in subtle yet persistent ways, such as the sensation of being watched whenever he passed the area where the floor should have been, or the faint, almost imperceptible sound of someone calling his name in a low, hoarse voice that seemed to rise from beneath the building itself, and though he tried to dismiss these occurrences as stress or imagination, they felt too consistent, too deliberate to be mere coincidence; one day, a new tenant in the building approached him, having heard rumors about the twelfth floor, and asked whether it was true that something had happened there in the past, mentioning vague stories of a fire or an accident, and the question triggered a distant memory in Ah Shing’s mind, something he had heard when he first started working there but had never paid much attention to at the time, a rumor of a devastating fire that had claimed multiple lives, and as he considered the possibility that the incident had occurred on the twelfth floor, a chilling realization took hold, connecting the fragments of his experiences into a pattern he could no longer ignore; from that moment on, he accepted that the twelfth floor was not simply an unused space but something else entirely, a place that existed within the building yet operated under a different set of rules, perhaps not meant for the living at all but for something beyond ordinary understanding, and he made a conscious decision to avoid it completely, no longer attempting to investigate or question its presence, because he understood that some boundaries are not meant to be crossed, and some truths carry consequences that are better left undiscovered; the building continued to stand in the quiet industrial district, unchanged in its outward appearance, and every night, as darkness settled over the city, the twelfth floor remained brightly lit, a silent anomaly hidden within an otherwise ordinary structure, its purpose unknown, its presence undeniable, and though no one could say who or what it was for, or what it might be guarding, its constant illumination served as a quiet warning to those who noticed it, a reminder that there are places in this world that do not belong to us, places that persist just beyond the edge of comprehension, waiting patiently, watching silently, and existing in a way that defies explanation, and even now, long after he stopped trying to understand it, Ah Shing could not help but wonder, whenever he glanced upward at the building in the dead of night, whether the lights on that floor were truly meant to guide, or whether they were simply ensuring that whatever remained there would never be left in darkness.