We moved into Unit 3B on a rainy Tuesday because it was the kind of deal you don’t ask too many questions about—fresh paint, “newly renovated,” a view of a skinny park across the street, and rent that was just low enough to feel like the universe had finally cut us a break. My wife, Nora, stood in the living room with a cardboard box balanced on her hip and said, half-laughing, “Either we’re the luckiest people in the city, or we’re starring in a cautionary tale.” I kissed her forehead and told her to stop watching horror movies before bed. Then Max trotted in behind us, nails clicking on the hardwood, tail swishing politely like he was meeting the apartment the way he met strangers: cautious, gentle, optimistic. We’d adopted him from the shelter a year earlier. The staff called him “a quiet old soul.” He looked like a shepherd mix with a dark muzzle and amber eyes that made you feel like he understood your secrets. For three months, everything was normal—if you don’t count the upstairs neighbor’s nightly tap-dancing and the way the hallway lights flickered like they were trying to speak in Morse code. We unpacked, we argued about where the couch should go, we painted one accent wall a brave shade of green that looked better in Nora’s head than it did in reality. Max claimed the corner of our bedroom beside the closet. He slept there with the steady confidence of a dog who believes the world, despite everything, is mostly safe. Then one evening, about a week into October, he stopped halfway through the bedroom doorway and froze. Not the usual “I heard a squirrel outside” freeze. Not even the “someone is at the door” freeze. This was different—his posture stiffened as if a wire had been pulled taut inside him. He stared at the wall to the right of our bed, the one that backed up to the building’s interior. His ears rose, his hackles lifted like a slow tide, and a sound came out of him so low and steady I felt it in my teeth. “Max?” Nora called, lowering a stack of folded towels. Max didn’t look at her. He didn’t blink. He just kept staring at that section of drywall as if it had suddenly become the only thing in the room that mattered. I laughed because that’s what I do when my brain can’t find the right box to store a feeling in. “He’s probably hearing pipes,” I said. “Old buildings talk.” Max’s growl deepened. Nora’s smile faded. “That’s… not pipes.” I walked over, put my hand against the wall, and felt… nothing. It was cool under my palm, smooth, painted a clean eggshell white. No vibration, no buzzing. “See?” I said, aiming for confident, landing closer to annoyed. “Nothing.” Max took one step forward and pressed his nose near the baseboard. He inhaled sharply, then backed away with a sound like warning. That night he refused to settle. He paced in slow circles, returning again and again to that spot, staring, growling, as if he was guarding us from something we couldn’t see. Around midnight, Nora whispered, “Ethan, I don’t like this.” I told her, “He’s anxious. New place, new sounds,” and I said it the way people say things they want to be true. The next day Max did it again. And the next. And the next. At first it was almost funny in an unsettling way—our calm, well-mannered dog suddenly obsessed with a patch of wall like it had personally insulted him. “Maybe there’s a mouse,” Nora suggested. “Or a raccoon. I heard raccoons can get into weird places.” “A raccoon,” I repeated, looking at our third-floor window and the smooth brick exterior. “Sure. A raccoon with an elevator.” She didn’t laugh. Max’s fixation wasn’t a quick reaction. He would stand there for hours. Not playing. Not wagging. Just watching. Like he was waiting for the wall to blink first. Then the scratching started. It began as soft, tentative taps—his claws lightly dragging down the paint, like he was testing it. Nora caught him one afternoon and snapped, “Max! No!” He flinched, not from fear, but from frustration, and looked back at the wall as if to say, You don’t understand. After that, the scratches grew deeper. He raked the baseboard, leaving raw white gouges through the paint. The sound was horrible—nails on drywall, a slow, stubborn scrape. I bought bitter spray from the pet store and coated the area until it smelled like a chemistry experiment. Max sniffed once, sneezed, and kept scratching. “Okay,” I muttered, trying not to let irritation become fear. “Okay, buddy. Message received.” Nights turned into something else entirely. At exactly 2:00 a.m., sometimes 2:07, sometimes 1:58, Max would rise from his bed like an alarm had gone off inside him. He’d go straight to that wall and begin a low, mournful howl that didn’t sound like a dog complaining. It sounded like a dog grieving. The first night I sat up, groggy, and said, “Max, stop.” He didn’t stop. Nora covered her ears, eyes wide in the dark. “He never howls,” she whispered. “He never does that.” The second night, the howling woke our downstairs neighbor, and the third night, it woke the entire building. On the fourth morning, a woman in pink curlers cornered me by the mailboxes and hissed, “If your mutt doesn’t shut up, I’m calling the landlord. Some of us have jobs.” Her name was Denise. She wore perfume that smelled like lemons and authority. I apologized and promised we were working on it. She leaned in like she wanted to be sure her words landed somewhere tender. “Work faster,” she said. That afternoon I called the building manager, a man named Graham Kline who always sounded like he was smiling while he lied. “Old buildings,” he said cheerfully. “Dogs pick up on things. The heating system, you know? Rattles in the walls.” “He’s scratching through the paint,” I said. “It’s one wall. Always the same spot.” “Then put furniture there,” Graham suggested, as if the problem was that Max had too much wall access. “Or maybe try one of those calming vests.” Nora snatched the phone from me. “We need maintenance to check,” she said, voice tight. “Now. There’s a smell sometimes, too. Like… like bleach.” I shot her a look. She shrugged helplessly. It was true. Some evenings, faint and sharp, we’d catch a chemical tang in the bedroom that made the back of my throat go dry. Graham paused just long enough to make it feel like we’d said something inconvenient. Then he went bright again. “We’ll send someone next week.” “Next week?” Nora repeated, the way you repeat a word when you can’t believe it exists in this conversation. “We’re not waiting a week.” “Ma’am,” Graham said gently, “I’m doing what I can.” He hung up with the same pleasant tone he’d started with, like we were discussing a leaky faucet and not a dog losing his mind at two in the morning. That night Max didn’t just howl. He trembled. I woke to the sound of his teeth chattering, a frantic clicking in the dark. When I turned on my phone light, he was pressed low to the floor, body rigid, staring at the wall as if it had grown teeth. His eyes were wide and glossy. He looked… trapped. “Max,” I whispered, reaching toward him. He flinched away from my hand, not because he was afraid of me, but because he couldn’t afford to look away from the wall for even a second. Nora sat up, hair wild, and breathed, “What is he looking at?” In the thin beam of light, the wall looked unchanged: clean, still, silent. And yet the air felt wrong, like the room had gained a second heartbeat. I pressed my ear to the drywall. I held my breath. For a long moment, there was only the hum of the city outside. Then—faintly—so faintly I thought my mind was inventing it—there was a sound. A soft, irregular tapping. Three taps, a pause, two taps. Max growled again, low and furious, as if answering. Nora’s hand gripped my arm so hard her nails dug in. “You heard that,” she whispered. I swallowed. “Yeah,” I said, and my voice came out smaller than I wanted. “I heard it.” The next morning we called an animal behaviorist because it was easier to pretend the problem lived in our dog than in our walls. Dr. Priya Patel arrived that afternoon with a tote bag full of treats and the calm face of someone who has seen every kind of human panic and learned not to catch it. Max liked her instantly, which should have reassured me. Instead it made me feel worse, because even while he accepted treats from her, he kept glancing at the bedroom hallway like he was checking to see if the enemy had moved. Dr. Patel crouched beside him, letting him sniff her hand. “Tell me what’s been happening,” she said. We told her. The growling. The staring. The howling at 2:00 a.m. The scratching through paint. The tapping. When I mentioned the tapping, she didn’t laugh. She didn’t dismiss it. She just tilted her head slightly, eyes narrowing, listening not to us but to the space around us. “Show me,” she said. We led her into the bedroom. Max stopped at the doorway like he always did, then stepped in and moved to his spot like a magnet had pulled him. He stared at the wall and let out that same low warning. Dr. Patel knelt, ran her fingers gently along the baseboard, then held still. “He’s not anxious,” she said quietly. Nora let out a breath like she’d been holding it for weeks. “Then what is it?” Dr. Patel looked at us, and for the first time her calm slipped, just a fraction. “He’s responding to something,” she said. “Dogs have incredible hearing. They can detect high frequencies, low frequencies. Subtle changes in smell. Movement in places you can’t perceive.” I tried to keep my voice practical. “Like… mice.” She shook her head. “Mice don’t usually produce this level of sustained fear response. This is… vigilance. Protective behavior.” Max scraped his claws once against the wall, like punctuation. Dr. Patel stood and turned to me. “Have you checked the building history?” “What?” I said. “Like… permits?” Nora frowned. “Why would we—” “Sometimes,” Dr. Patel said gently, “animals react to things we don’t consider. Hidden spaces. People living in walls. Gas leaks. Mold. Electrical issues. I’m not trying to scare you. I’m trying to keep you safe.” She paused, then added, “If you heard tapping, you need to treat that as real until proven otherwise. Call maintenance again. If they won’t respond, call the landlord. If they still won’t respond, call the police for a welfare check. Say you believe someone might be trapped.” Nora’s eyes went shiny. “Someone trapped,” she repeated, voice cracking as if the phrase had claws. After Dr. Patel left, we did what responsible adults do when reality feels too sharp: we tried to outsource the fear. We called Graham again. Straight to voicemail. We emailed. No reply. We left messages with the property office. Nothing. That evening Denise knocked on our door with the fury of someone who believes the world owes her quiet. “Your dog kept me up again,” she snapped. “I’m calling the city.” Nora opened her mouth to argue, but Max padded forward, stopped behind Nora’s legs, and growled—not at Denise, but toward the bedroom. Denise’s expression flickered. “What’s wrong with him?” she demanded, taking one step back. “We think there’s something in the wall,” Nora said, and the words came out in a rush, like she’d been trying not to say them for days. Denise’s laugh was sharp. “In the wall. Sure. You two are—” A faint tapping sounded from the hallway behind us. Denise froze mid-scoff. Her eyes darted toward the bedroom. “What… what was that?” she whispered. I saw something shift in her face then: irritation turning into the first edge of fear. Denise swallowed hard and backed away. “Get your… your wall ghosts under control,” she muttered, and hurried down the hallway like the building had suddenly become a stranger. That night Max didn’t howl. He did something worse: he went silent. He sat rigidly facing the wall, ears forward, body tense, like a soldier listening for footsteps outside a tent. At 2:03 a.m., the tapping started again. It wasn’t steady. It was desperate. When I pressed my ear to the drywall, I could hear it clearly now: a pattern. Tap-tap-tap. Pause. Tap-tap. Pause. Tap-tap-tap. Like someone trying to speak without a voice. Nora covered her mouth with both hands, eyes huge. “Ethan,” she whispered, “that’s a person.” I should have called the police then. I know that now. But fear makes you stupid in specific, creative ways. It makes you bargain. It makes you say, Maybe it’s pipes, maybe it’s animals, maybe it’s the building settling, because the alternative is too heavy to lift. And there was another thing—pride. The stupid male pride of not wanting to be the guy who calls 911 because his dog is growling at drywall. So instead I did what I told myself was “taking control.” I said, “Tomorrow. We deal with it tomorrow. We’ll open it up ourselves. We’ll prove it’s nothing.” Nora stared at me like I’d just volunteered us for a cliff dive. “You want to… break the wall?” “Just a small section,” I said, already picturing myself as the rational hero who solves the mystery with a hammer and common sense. “We’ll find a dead rat nest or a loose vent or something.” Max let out a sound that wasn’t a growl or a whine—something in between, raw and urgent. Nora whispered, “He doesn’t want us to.” “He doesn’t want us to what?” I snapped, too loud, too defensive. “He’s a dog.” The moment the words left my mouth, I regretted them, because Max looked at me then. Really looked. His amber eyes were wet and pleading, and for a second I felt something cold settle in my chest like a stone. The next day I called my friend Cal, who’d done construction work since high school and kept tools in his truck like other people kept gum. “You want to knock a hole in a wall?” he said, amused. “In a rental?” “It’s complicated,” I told him. “We think there’s… something behind it.” “Something like a safe?” Cal asked. “Something like… a person,” I said. There was silence on the line. “I’ll be there in an hour,” he said, and his tone had changed completely. Cal arrived with a toolbox, a stud finder, and a seriousness I’d never seen on him. Nora paced the living room, phone in hand, debating whether to call 911. “We should call now,” she said. “Before we do anything.” “If we call and it’s nothing,” I argued, “we look insane.” “I don’t care how we look,” she snapped. “I care if someone is in there.” Max hovered near the bedroom door, trembling with a kind of restrained panic. Cal stepped into the bedroom, glanced at the scratched paint, and whistled low. “Man,” he murmured, running a finger along the gouges. “Your dog was trying to dig to China.” He pulled out the stud finder, pressed it to the wall, moved it slowly. It beeped. He frowned. He moved it again. “That’s weird,” he said. “What?” I asked. “The studs,” he said. “Spacing is off. Like… there’s a section here that isn’t framed normally.” Nora’s face drained. Cal knocked gently. The sound was dull in most places—solid. But when he knocked at one spot about two feet off the floor, the sound changed. Hollow. My stomach tightened. Max began to whine, a high, distressed sound, and pressed himself against Nora’s legs. “Okay,” Cal said softly, as if speaking loudly might awaken something. “We do this carefully. Small opening. We don’t go swinging like it’s demolition day on TV.” Nora nodded rapidly. “We call the police,” she whispered. I hesitated one last time—then the tapping came, faint but unmistakable, from inside the wall. Tap-tap-tap. I felt my pride shrivel into ash. “Call,” I said, and my voice finally matched the fear in the room. Nora dialed 911 with shaking fingers. While she spoke to the dispatcher—“We hear tapping inside our wall, our dog’s been reacting for weeks, we think someone might be trapped”—Cal marked a square on the drywall with a pencil. Max started barking, frantic, then ran to the bedroom door and threw his body against it as if he could push us out of the room. “Max!” Nora cried, tears spilling. “Baby, please—” Cal lowered his voice. “Your dog’s not trying to stop you because he’s afraid of the wall,” he said. “He’s afraid of what you’ll find.” He took a utility knife and cut along the pencil lines with slow precision. The first layer gave way with a soft crack. Dust drifted out like breath. The smell hit me immediately—stale air, old insulation, and something else beneath it, something sour and metallic that turned my stomach. Cal pulled the cut square away and shined a flashlight inside. His face went still. “Oh,” he said, very quietly. “Oh, no.” Nora grabbed my arm. “What?” she demanded. “What is it?” Cal didn’t answer right away. He reached in carefully and drew something out. It was a strip of fabric—dirty, frayed. Then another. Then he reached in again and his fingers came out with something that made my blood run cold: a cracked smartphone, its screen spiderwebbed, its case stained. Nora covered her mouth with a sob. Max barked wildly, then bolted to the front door, scratching at it, crying like he needed to escape the apartment itself. “There’s a cavity back here,” Cal said, voice tight. “Not just insulation. Like a space. Someone made a… like a crawlspace.” “Is there someone in there?” I asked, my throat burning. Cal moved the flashlight. I leaned in. In the narrow beam, I saw it: a hidden void between the walls, larger than it should have been. There was a blanket bunched in the corner, flattened like someone had slept on it. There were plastic water bottles—empty. A small pile of snack wrappers. And on the far side, a metal panel, screwed shut, like a second door inside the wall. Nora whispered, “Oh my God.” The tapping came again, louder now, as if our opening had given it permission. Tap-tap-tap. Pause. Tap-tap. It wasn’t coming from the cavity Cal had opened. It was coming from behind the metal panel. “That’s… that’s behind that,” I said, pointing with a trembling hand. Cal swallowed. “Yeah.” Outside, we heard footsteps pounding up the stairs—too fast, too heavy. The dispatcher was still on the line when someone slammed a fist against our apartment door. “Open up!” a man barked. Cal’s eyes widened. “Who the hell is that?” Nora’s face went white. “It’s Graham,” she whispered. “The building manager.” Another bang. “OPEN THE DOOR!” Nora’s voice shook as she spoke into the phone, “He’s here. The building manager is here and he’s yelling.” The dispatcher’s tone sharpened. “Ma’am, do not open the door. Officers are en route. Stay inside. Stay away from the door.” Graham pounded again, harder, like he could batter his way through. “I know you’re in there!” he shouted. “You’re damaging property! Put the wall back—NOW!” Cal moved between Nora and the bedroom doorway, as if his body could become a shield. I felt a surge of anger through the fear. “Why are you here?” I yelled back. “We called you for weeks!” Graham’s voice snapped, losing its pleasant mask. “Because you’re not supposed to touch that wall,” he hissed, and the way he said it—sharp, possessive—made my skin prickle. Max returned from the door and stood in the hallway, barking, then growling low, his body angled toward the bedroom and the front door at once, like he couldn’t decide which threat was worse. Graham’s voice dropped to something almost calm. “Ethan,” he called, as if we were friends. “Listen to me. Step away from that wall. You don’t know what you’re messing with.” Nora’s voice cracked. “What’s in there, Graham?” Silence. Then, softer: “Nothing good.” He hit the door again, and this time the frame rattled. Nora began to cry. “Police are coming,” she whispered. “Please, just… please.” Cal leaned close to me. “We need to keep him out,” he murmured. “And we need to keep that hole open. If someone’s alive in there…” His eyes flicked toward the metal panel. Tap-tap-tap. Faster now. Panicked. I moved toward the bedroom, heart hammering, and Cal grabbed my wrist. “Don’t,” he warned. “Wait for the cops.” “If someone’s in there—” I began. “If you open that panel and something goes wrong, we can’t put it back,” he said, voice harsh with fear. “We can’t fight a grown man in a hallway with a dog and a hammer.” Graham’s fist slammed again. “Last chance!” he roared. Then, to my horror, I heard the distinct sound of a key sliding into our lock. Nora’s eyes went huge. “He has a key,” she whispered. “Of course he has a key.” The lock turned. The door began to open. Max exploded into motion, lunging forward with a bark that sounded like fury made audible. Cal grabbed the sledgehammer from his bag—not to attack, but to brace. I shoved a chair against the door, but it was already giving. “Back!” Cal shouted. “Back—” The door pushed inward with a crack, the chain snapping because I hadn’t latched it, because I never thought I’d need to. Graham forced his shoulder through, face red, eyes wild. He froze when he saw the hole in the bedroom wall. Something like panic flickered across his face, and then rage swallowed it. “What did you do?” he spat. Nora screamed, “Get out!” Graham’s gaze snapped to her, then to Max, then back to the hole. “You don’t understand,” he said quickly, too quickly. “You’re going to make it worse.” “Worse than what?” I shouted. “What is behind that wall?” Max bared his teeth and growled, deep and unmistakable. Graham took one step toward the bedroom. Cal stepped in front of him, sledgehammer raised. “You take one more step, I swear—” Cal began. Graham’s eyes darted toward the front door behind him, like he was calculating escape routes. “Give me the phone,” he snapped at Nora. “Right now.” Nora clutched it tighter. “No.” Graham’s face twisted. “You called the cops,” he realized, and the color drained from him. “You idiots,” he breathed. “You absolute—” Sirens wailed outside, faint but approaching, and Graham’s head jerked toward the sound like a hunted animal. He backed up instinctively. Max surged forward with a bark, driving him toward the door. Graham snarled and swung his arm as if to shove Max away. Max lunged—teeth snapping, not in play but in protection—and clamped onto Graham’s forearm. Graham screamed, a raw sound of pain and shock. “Get it off!” he shrieked. “Get it—” Cal grabbed Graham’s shirt and shoved him hard, forcing him backward. Graham stumbled into the hallway just as two police officers appeared at the top of the stairwell, guns drawn, voices loud and commanding. “Police!” one shouted. “Hands where we can see them!” Graham froze, clutching his bleeding arm, eyes darting wildly. “You don’t understand,” he stammered. “They— they broke the wall—” “On the ground!” the officer barked. Graham dropped, shaking, and another set of footsteps thundered up behind them—more officers, and a woman in a dark jacket with a badge clipped to her belt. Detective Reyes, her nameplate said when she stepped into our apartment and took in the hole in the wall, the frantic dog, Nora sobbing against my shoulder, Cal gripping a sledgehammer like it was the only solid thing in the world. Detective Reyes lifted a hand, steadying the chaos with her presence. “Everyone breathe,” she said firmly. “Start from the beginning.” My voice came out hoarse and broken as I explained—Max’s behavior, the tapping, Graham’s refusal to help, the hidden cavity. Detective Reyes listened without interrupting, her eyes narrowing as she approached the hole. An officer shined a brighter flashlight into the void. Detective Reyes leaned in, and I saw her jaw tighten. “Clear the room,” she ordered. “Now. We’re treating this as a possible confinement.” Nora clung to me as officers guided us into the living room. Max paced, whining, trying to follow them back to the bedroom. Detective Reyes knelt and spoke to him softly, surprising me. “Good boy,” she murmured, and Max, trembling, sat but kept his eyes locked on the bedroom doorway. It took the officers less than a minute to unscrew the metal panel—four rusted screws that squealed as they turned, as if the wall itself protested. When the panel came loose, a rush of air spilled out, colder than the room, smelling of damp concrete and something human—sweat and fear and stale breath. For a heartbeat, there was silence. Then a voice, small and cracked, came from the darkness beyond. “Please,” it whispered. “Please don’t close it.” Nora let out a sob so hard it sounded like it hurt. The officers moved fast, flashlights cutting through the narrow space. “Ma’am?” an officer called. “Can you tell me your name?” The voice trembled. “Harper,” it said. “Harper… I’m here. I’m here.” There was shuffling, then a pale hand appeared through the opening, fingers shaking like they weren’t sure they were real. Detective Reyes’ voice gentled. “Harper, you’re safe. We’re going to get you out.” It took them time—careful, methodical—because the space was tighter than it should have been, because whoever had sealed it had done it on purpose. When they finally pulled her free, Harper was so thin she looked like she could fold in half. Her hair was tangled, her lips cracked, her eyes huge in a face streaked with grime. She blinked at the light like it was painful, then her gaze locked on Max. Something broke in her expression. She reached out a trembling hand. “That dog,” she whispered, voice thick with emotion. “He… he heard me.” Max approached slowly, then pressed his forehead against her knee with a whine that sounded like relief made visible. Harper began to cry, silent tears sliding down her cheeks. Detective Reyes’ eyes snapped to Graham, who was being held in the hallway, pale and shaking. “You want to explain this?” she demanded. Graham’s mouth opened and closed. “I— I didn’t—” “Save it,” Reyes snapped. “You’re done.” The story spilled out later in pieces, ugly and unbelievable: Harper had been reported missing two months before we moved in. She’d been a grad student, new to the city, taking a job at a café near the building. She’d trusted the wrong person. Graham had noticed her, offered help, offered a “discount unit,” offered a ride when it rained. He’d taken her keys. He’d told her no one would hear her in an old building. He’d been wrong—because Max did. Because a dog with the soul of a guardian refused to accept a lie as reality. When the paramedics took Harper away on a stretcher, she grabbed my sleeve weakly. “I heard you two,” she whispered, eyes shining. “I heard your voices. I thought I was dreaming. I thought… I thought I died.” Nora clasped her hand. “You’re alive,” she choked out. “You’re here. You’re safe.” Harper’s gaze flicked to Max again. “Tell him,” she whispered. “Tell him thank you.” Nora leaned down, pressed her forehead to Max’s, and whispered through tears, “You saved her. You saved all of us.” After the police left, after the paramedics left, after the hallway filled with murmurs and neighbors peeking through cracked doors like they were watching a show they couldn’t admit they wanted, the apartment felt different—hollowed out, haunted not by ghosts but by the fact that something real and terrible had been hidden inches from our bed. Denise stood in the hallway in her slippers, face white, and for once she didn’t have anything sharp to say. She just stared at us and whispered, “I’m sorry.” Cal sat on our couch, hands shaking, staring at his dusty boots as if he couldn’t believe they were still on solid ground. “Man,” he said hoarsely. “Your dog…” I looked at Max, who lay in the bedroom doorway like a sentry, eyes fixed on the broken wall, and I felt my own knees threaten to buckle. “Yeah,” I whispered. “My dog.” We didn’t sleep in that bedroom again. We didn’t stay in that apartment more than another week. The landlord—a corporate company with a smiling logo and a dozen shell emails—sent a representative who talked in rehearsed sympathy and offered us “a relocation option,” as if the horror could be handled like a paperwork inconvenience. Nora nearly screamed at him. Detective Reyes later told us, quietly, that our call had cracked open more than one case. “These hidden spaces,” she said, eyes tired. “They’re used for things people don’t want found. Your dog changed the timeline.” We moved into a different place across town, a smaller apartment with too much sunlight and walls that sounded honest when you knocked on them. For a while, Max slept like he was making up for lost time. He ate with new enthusiasm. He stopped howling at 2:00 a.m. Nora’s laughter came back in small pieces. And yet, some nights, when the city was quiet and the air felt too still, Max would lift his head abruptly and stare at a corner of the room—just for a second, just long enough to make my heart stop—then he’d blink, sigh, and rest his chin back down as if he’d decided, No. Not here. Not anymore. But I never forgot the look in his eyes the first time he faced that wall, the way he stood between us and the unknown with nothing but his body and his instinct and a stubborn refusal to look away. People like to say dogs can sense evil. After Unit 3B, I didn’t think of it as a cute phrase anymore. I thought of it as a fact written in claw marks and sleepless nights and the sound of tapping in the dark—three taps, a pause, two taps—like a human heart trying not to be forgotten, until a dog finally insisted the world listen.