By eight-fifteen the next morning, Luke had apparently been in Lab 7 long enough to drain half a pot of coffee. The smell of dark roast was already competing with machine oil when I dropped my bag beside the terminal and woke the displays. He was already at the rig, sleeves rolled to his elbows, resting one flat palm against the heavy metal frame while the motor hummed. "Right," Luke said, running a hand through his dark hair as I logged in. "So the computer says this thing is shaking itself apart, but I'm standing here touching it and feeling absolutely nothing." "The sensor reading is clean, steady, and repeatable," I said, pulling up the monitoring interface and tapping the display with the back of a pen. "It doesn't behave like a random glitch. It looks like an actual vibration." Luke dragged a rolling stool over from a neighboring workbench, dropping onto it with an easy, fluid motion. He pulled up right beside me, close enough that his shoulder brushed the fleece of my sweater. He smelled like fresh coffee, machine oil, and cold metal—a combination that my brain unhelpfully cataloged before I could force my attention back to the monitors. "Then let's test it step-by-step," he said, resting his forearms on the edge of the desk. "We run through every speed and setting. You watch the data on your end, I’ll work the controls on mine." "Methodical," I said, a faint smile touching my mouth. "I like it." "Sounds like a plan, Mercer." His grin was quick and entirely unbothered. "Let's find the fault." Over the next two hours, we fell into a rhythm. He called out the settings, his voice steady over the ambient drone of the room. "Starting test run one. Main drive on. Pressure normal." "Confirmed," I answered, typing. "System is logging." On my screen, the line stayed completely flat. We moved through the machine's paces: low speed, medium speed, changing how hard the motor pushed. When the machine was just idling or running smooth and steady, the sensors stayed quiet. "Okay," I muttered, blowing an escaping curl out of my glasses. "It doesn't happen when the machine is running normally. It only acts up when it's being pushed." Luke leaned back, locking his hands behind his head and stretching his arms wide. The motion pulled his canvas shirt taut across broad shoulders, and I found myself staring intently at a completely uninteresting column of numbers until he dropped his arms back down. "Let's push it, then," Luke suggested. "Run the high-stress test." He flipped the switches on the console. "Test run three. Max speed, rapid stop-and-start." A sharp whine rose from the motor, followed immediately by a tall, rhythmic spike marching right across my screen. "There!" I pointed at the red line climbing past the safety limit. "Right there! It's doing it again!" Luke leaned forward instantly, planting his palm flat against the heavy metal casing. His fingers spread wide across the cold steel, jaw set as he concentrated. "Nothing," he said, shaking his head slowly. "It's dead calm, Mercer. The metal isn't even trembling." "It only trips under heavy load," I said, a hum of pure curiosity kicking in. We hadn't solved it, but we finally had a target. "We can make it happen on command." He turned to look at me, hazel eyes catching the fluorescent light, the dimple in his cheek showing. He held my gaze for a beat, a quiet, shared nod passing between us that felt more satisfying than any victory lap. "Alright," Luke said, leaning back with a breath. "We know when it happens. Now we start changing one variable at a time until we figure out which one matters." "Exactly," I agreed. "Something is reaching the sensors. We just have to figure out what." Finding the trigger didn't tell us the cause. The rest of the day disappeared into variations of the same test, systematically altering motor cycles, cable routing, and which sensors were active. Every run offered just enough inconsistency to keep the answer hovering half a step out of reach. By the time half the overhead lights switched off for the evening, we'd narrowed the problem without solving it, leaving our corner bathed in the glow of the dual monitors and the desk lamp. My stomach chose that exact second of quiet to let out a loud, traitorous growl. Luke’s mouth curved. "Hungry?" "My digestive tract is submitting an urgent support ticket," I admitted. Before he could answer, the lab door swung open. Marc stuck his head in, jacket already zipped, gym bag slung over one shoulder. "Still here?" Marc asked, eyeing the workbench. "Did you two break the rig, or is it breaking you?" "We found the trigger, Marc," Luke said without looking up from his notes. "Go home. Some of us actually work for a living." "Right. Have fun explaining to Dana why you're living in Lab Seven." Marc gave a two-finger salute and let the heavy door swing shut. Luke pushed his chair back and stood up, digging his phone from his pocket. "Asteron's cafeteria closed at five, but the Chinese place three blocks over is aggressively greasy and stays open late. Lo mein?" "Deal," I said. "As long as it's not from a vending machine." Twenty minutes later, two brown paper bags were parked on a cleared corner of the metal workbench. The food was, as advertised, outrageously greasy, lukewarm, and entirely satisfying. We ate perched on high stools, balancing cardboard takeout boxes between tools and stacks of printed diagrams. We talked about the machine, but the conversation kept spilling over the edges. Luke mentioned a Wednesday pub trivia night he went to with friends, which led to a fifteen-minute debate over whether anyone actually knew the inventor of the modern zipper. "Whitcomb Judson," I said through a mouthful of noodles. "Later perfected by Gideon Sundback. It’s fundamental engineering history." Luke stared at me, chopsticks suspended halfway to his mouth, his hazel eyes crinkled with genuine delight. "You're terrifying, Mercer. You know that, right?" "I'm informed," I deadpanned. By the time we cleared the cartons and set the automated tests to run overnight, it was past eight. The central hallway was deserted, our footsteps echoing against the floor as we walked toward the exit. Outside, the evening air was crisp and dark. We walked across the half-empty parking lot toward the rows of quiet cars, the talk lingering on petty office complaints and the sheer absurdity of Asteron’s badge-replacement fees. We stopped between my compact hatchback and his beat-up silver truck. Luke leaned one elbow against the tailgate, keys dangling from his calloused fingers, looking at me with that calm, unhurried ease that seemed built directly into his spine. "I'll be in early tomorrow," he said, the corner of his mouth ticking up. "Figure I'll grab a different sensor cable before everyone raids the parts bins." "Good idea," I said, shifting my laptop bag higher on my shoulder. I unlocked my car, dropped into the driver’s seat, and pulled out my phone. I slid my morning alarm fifteen minutes earlier, locked the screen, and started the engine.

Chapter 3: Second Shift