The first time Sarah walked in her sleep, I thought it was stress. She’d been working late shifts at the hospital, coming home exhausted, her scrubs still smelling of antiseptic and something else I couldn’t place. That night, I woke to find her standing at the foot of our bed, perfectly still, her eyes open but vacant.

“Sarah?” I whispered, but she didn’t respond. She turned and walked toward the window, her bare feet silent on the hardwood floor. I’d read somewhere that you shouldn’t wake a sleepwalker, so I followed at a distance, watching as she pressed her face against the glass and stood there for nearly an hour before returning to bed.

The second time, she made it to the kitchen. I found her standing in front of the open refrigerator, the cold light casting her in an ethereal glow. Her nightgown billowed slightly in the artificial breeze, and she was humming something low and melodic—a tune I’d never heard before. When she finally closed the door and returned to bed, I checked the refrigerator. Nothing was missing, but everything on the top shelf had been rearranged in a perfect circle.

I mentioned it to her the next morning over coffee. Sarah laughed it off, claiming she had no memory of it. “Maybe I’m more tired than I thought,” she said, but there was something in her eyes—a flicker of recognition she was trying to hide.

The walks became more frequent. Every few nights, I’d wake to find her side of the bed empty and cold. I started following her, documenting her routes through our suburban home. Kitchen to living room to front door, where she’d stand with her hand on the deadbolt for exactly thirteen minutes—I timed it. Then back to the kitchen, where she’d open every cabinet door and leave them that way.

But it was the fourth week when things changed.

I woke to find Sarah in the bathroom, standing naked in the bathtub with the shower running cold. Her skin was covered in goosebumps, her lips blue, but she showed no signs of discomfort. She was washing herself methodically, scrubbing with a washcloth that wasn’t there. Her movements were mechanical, repetitive, like she was trying to clean something that wouldn’t come off.

When I tried to turn off the water, she grabbed my wrist with surprising strength. Her eyes snapped open—not waking up, but opening—and she looked directly at me. But it wasn’t Sarah looking back. The expression was wrong, ancient somehow, like something old was peering out through her features.

“She’s still dirty,” Sarah said in a voice that wasn’t quite her own. “She needs to be clean before they come for her.”

Then she blinked, and it was Sarah again, confused and shivering. I wrapped her in a towel and led her back to bed, but sleep didn’t come easy after that.

I started researching sleepwalking, diving deep into medical journals and obscure case studies. Most sources said it was harmless, caused by stress or sleep deprivation. But I found other accounts—older ones—that described something different. Somnambulism as a doorway, a state where the conscious mind stepped aside and let something else take the wheel.

The night Sarah walked outside, I knew we’d crossed a line.

I woke to the sound of the front door closing. By the time I threw on clothes and followed, she was already at the end of our street, walking with purpose toward the old cemetery that bordered our neighborhood. Her white nightgown fluttered behind her like a ghost, and her feet moved with certainty despite the darkness.

She walked through the cemetery gates as if they were open, though I had to climb over the chain-link fence to follow. Sarah moved between the headstones with familiarity, stopping at a grave I’d never noticed before. The headstone was old, weathered, the name barely visible: Margaret Henley, 1847-1871, Beloved Daughter.

Sarah knelt beside the grave and began digging with her bare hands. The soil came away easily, too easily, as if it had been disturbed recently. Her fingernails split and bled, but she showed no sign of pain. She hummed that same melody from the kitchen, and now I recognized it—a lullaby, something a mother might sing to a sick child.

When she reached something solid, she stopped. From the hole, she pulled out a small wooden box, rotted and falling apart. Inside were the bones of what looked like a baby, yellowed with age. Sarah cradled the remains against her chest and began to rock back and forth.

“I’m sorry,” she whispered, and for a moment I thought she was awake. “I’m so sorry I couldn’t save you.”

But when she looked up at me, those weren’t Sarah’s eyes staring back.

“She was a nurse, you know,” the thing wearing my wife’s face said. “Back when medicine was more prayer than science. So many babies died in her care. So many mothers blamed her. They said she was cursed, that death followed her wherever she went.”

The voice was different now—older, with an accent that belonged to another century. Sarah’s lips moved, but the words weren’t hers.

“Margaret tried to save them all, but the fever took them anyway. One by one, until the mothers came for her with stones and accusations. They buried her here, but they wouldn’t let her rest. Not until she made amends.”

Sarah—or Margaret—stood up, still holding the tiny bones. “Your wife works at the hospital. She sees the ones who don’t make it, feels their pain. Margaret recognized a kindred spirit.”

The cemetery around us seemed to shift and blur, headstones multiplying in my peripheral vision. I could hear whispers in the wind, voices of women calling out names—baby names, each one a small tragedy.

“What do you want?” I managed to ask.

“To finish what was started. To save the ones who can still be saved.” Sarah’s body began walking toward the cemetery exit, carrying the bones like a precious offering. “Your wife understands. She’s been helping, bringing the sick ones here where Margaret can tend to them properly.”

That’s when I remembered the smell on Sarah’s scrubs—not antiseptic, but earth. Cemetery earth.

I followed them home, my mind reeling with the implications. How many nights had this been happening without my knowledge? How many times had Sarah—or Margaret—taken this walk?

Back in our bedroom, Sarah placed the bones in her nightstand drawer and returned to bed as if nothing had happened. But I noticed things I’d missed before: the mud under her fingernails that never seemed to wash clean, the way she sometimes spoke to empty corners of the room, the hospital reports she’d been bringing home and burning in our fireplace.

The next morning, Sarah seemed perfectly normal. She made coffee, kissed me goodbye, and went to work like any other day. But when I checked her nightstand drawer, the bones were gone. In their place was a note in handwriting that wasn’t Sarah’s:

The children are safe now. Margaret is at peace. But Sarah has seen too much, felt too much. The boundary is thin for those who care too deeply. Watch her closely, or you’ll lose her to the space between sleeping and waking, where the dead still have work to do.

That night, I pretended to sleep and waited. Sure enough, Sarah rose and began her walk. But this time, she didn’t head for the kitchen or the bathroom. She walked directly to our bedroom window, opened it, and stepped out onto the second-story ledge.

I lunged forward, grabbing her arm just as she prepared to step into empty air. Her eyes opened—Sarah’s eyes this time—and she looked at me with such profound sadness that it broke my heart.

“I can hear them crying,” she whispered. “All the ones I couldn’t save. They’re calling to me, David. They want me to come with them.”

I pulled her back inside and held her tight, feeling how thin she’d become, how cold her skin was. “You’re not going anywhere,” I said, but even as I spoke the words, I could feel her slipping away.

The sleepwalking stopped after that night, but Sarah never fully returned. She moved through our house like a ghost, her eyes always focused on something I couldn’t see. Sometimes I’d catch her humming that lullaby, her hands moving as if she were rocking an invisible child.

The hospital transferred her to administrative duties after she was found in the children’s ward at three in the morning, standing over empty cribs and whispering apologies to the air. They said it was a breakdown, stress-related. They recommended therapy, medication, time off.

But I know the truth. Margaret may be at peace, but she left something behind—a door between worlds that Sarah opened in her sleep. And now my wife stands guard at that threshold, keeping watch over the children who exist in the space between life and death, forever walking the line between sleeping and waking, between sanity and something far more terrible.

Every night, I watch her sleep, waiting for the moment she’ll rise and walk again. Because I know that one night, she won’t come back. She’ll follow those phantom children into whatever realm they inhabit, leaving me alone with the knowledge that love isn’t always enough to anchor someone to this world.

And sometimes, in the darkest hours before dawn, I think that might be a mercy.