My sister called me at midnight and whispered, “Turn off every light. Go to the attic. Don’t tell your husband.” I thought she was losing her mind — until I looked through the floorboards….

I answered the call in a whisper, my throat tight. “Mara?”

Her voice was not the one I knew. It was stripped of all warmth, all sisterly affection. It was a wire pulled taut to its breaking point. “Listen to me very carefully, Elise. Don’t ask questions yet. Just listen. Turn everything off. Your phone’s screen, the lamps, the monitor. Everything that makes light or sound. Go to the attic, lock the door from the inside, and do not, under any circumstances, tell Caleb.”

A chill, profound and deeply primal, snaked its way up my spine. It was a cold that had nothing to do with the temperature of the room. “What? Mara, what are you talking about?”

“Now, Elise.” The command was absolute.

My eyes darted to my husband. Caleb lay facing away from me, a silhouette under the comforter. His breathing remained slow and steady, the picture of peaceful slumber. He had kissed my forehead three hours ago and whispered, “Sleep well, baby.” He had smiled.

“You’re scaring me,” I whispered into the phone, my voice trembling.

Mara’s voice, which had been a tense whisper, suddenly snapped into a shout so sharp it felt like a physical blow. “Just do it!”

The sheer, unadulterated panic in her voice propelled me into motion. Thought ceased; instinct took over. I slid out of bed, my bare feet hitting the cold hardwood floor. My hand, acting on some bizarre autopilot, snatched my phone charger from the nightstand before I crept into the hallway. The old floorboards groaned under my weight, a sound that seemed to deafen me.

Behind me, in the bed, Caleb shifted. The rustle of sheets was like an explosion in the silence.

“Elise?” he murmured, his voice thick with sleep.

I froze, my body rigid, every muscle screaming. I held my breath, waiting for the world to collapse.

“I’m just getting a glass of water,” I managed to say, my voice a surprisingly steady lie.

He didn’t respond. A soft snore a moment later told me he had slipped back into sleep. I let out a breath I hadn’t realized I was holding, my lungs burning.