The question keeps coming to mind, popping up at odd moments. It’s unnerving, unsettling, but you have to ask: “Is someone in the house?”

The question has plagued you for days and doesn’t seem ready to resolve itself anytime soon. You don’t mean your wife and daughter, the ones you expect to be here. Nor do you think it’s your mother or brother-in-law, both of whom have spare keys. No, what you’re thinking is an intruder, someone who’s not supposed to be here, someone who unbeknownst to you is living in the closets and crawlspaces, someone who creeps around whenever you’re away, whenever you’re not looking, whenever you’re tucked in bed at night.

You shake it off. Paranoia. There’s no reason to think this, but it persists.

Is someone here? Someone who’s not supposed to be?

You listen at night. The heater goes on. The hardwood floors heave. Expand. Contract. The sounds an old house makes. You listen between your wife’s respirations, her gentle sleeping breath.

Who’s there? What’s that?

Next door, the neighbor climbs the stairs. You live in a twin. These are the sounds you hear living in a twin. But maybe it’s something else, someone on the floor below. Your arms and legs lock in fear, but you shake them loose. You grab the baseball bat from next to your bed and wander into the hall.

It’s dark, but your eyes adjust. A clanking comes from downstairs. It might be the vents. You sneak along, avoiding spots where the floorboards squeak, hoping you don’t wake your one-year-old daughter. If she makes noise, alerting whoever’s in the house to her presence, the intruder could grab her, use her against you. You think about this whenever you consider someone breaking in. How you’d have to get out in front and guard your family. If you don’t, they might take her and tell you to put down the bat, and you’d have to do it, knowing all the while that the intruder would likely cause the same harm whether you fight back or not.

You peek in as you pass your daughter’s door and see her move beneath the blankets. She’s safe for now. You hit the top step and pad down. You take each one slow, holding the bat. You played some ball in high school, and though you weren’t a slugger, one swing at a man off-guard and you’d likely have him down, maybe kill him. But you don’t want that. Or maybe you do. You don’t consider yourself a violent man, but you’d become one if your family was threatened. You reach the bottom step, slide back the safety gate, and step out ready to swing. You flick on the light, but no one’s there. It’s all in your head.

But is it?

Your daughter’s pink princess car has moved across the room. Her stuffed bear is sitting in a different spot. You were the last one up, so you’d know. You’d left the bear on the sofa and now he’s in the rocking chair. The car had been tucked in a corner, and now it’s in the center of the rug. It’s strange, but maybe you’re wrong.

 That was how you left it, right?

You check the locks and windows and sit and doze. You wake to your daughter’s cries and run upstairs. It’s morning now. You don’t have time to fret. It’s time to get her to daycare and go to work. It’s time to forget how foolish you’ve been. By day, everything’s clear. You made it up. But once you get home, it starts again. Whenever you’re alone and your mind’s not occupied with the basic tasks of living, it tugs at you. You can’t let it drop.

From the time you rented your first apartment, you’ve been aware that someone could break in. Before this, when you lived in your parents’ house, it never occurred to you. You’ve read books on how to defend yourself. If someone wants to steal from you, the books say, they’ll choose a time when you’re not home. If someone breaks in and you’re there, you have to assume they mean you harm. The best way to avoid getting killed is to avoid conflict altogether, and whenever you’ve selected apartments, you’ve had two considerations: first, how easily you could escape in case of fire; second, how hard breaking in would be.

Your first apartment was on the fourth floor. Dead bolts on the doors. A neighboring rooftop you could jump to in case of conflagration. Your second was a third-floor walkup, much the same, and while your last apartment was on the first floor, its windows were high enough that intruders would need a ladder to get in. It was a cheap two bedroom space you couldn’t pass up. But there was a bar nearby, and you woke all hours of the night to hear people passing beneath, so you started sleeping with a hammer under your pillow. You’ve always favored blunt force objects for self-defense. A gun would make things easier. But that’s exactly what puts you off. Too easy for an accident, too. Especially with a kid in the house. When you and your wife started dating, she’d found the hammer and made fun of you. When you moved into your house, she laughed even harder when you ordered the baseball bat and it arrived with a logo that reads, “Hammer” written across the barrel. This wasn’t intentional. Rather, it’s mere coincidence. Yet, you’ve placed this hammer next to your bed, and you sleep with it there, just in case.

A few days have passed since you crept downstairs and noticed that someone moved your daughter’s toys. You’ve tried to forget about it. Yet, the noises you hear at night still disturb you. Each time the house shifts, you freeze up, listening. It rains Sunday night. Certain drops are louder than others. They sound like footsteps coming up the stairs, and you sleep in short bursts and wake at the slightest noise: laughter on the street outside, a car pulling up.

 Drip. Tick. Scratch. Creak.

If it’s rhythmic, it’s not an intruder. Besides, who’d sneak in after you went to bed just to move toys around? The house is old, right? And old houses make noises. You pull the covers to your chin and lay on your back to free both ears so you’ll hear everything. The rain turns to snow at two, and you wake at five-thirty to your daughter’s cries. It’s Monday, so you rise and head outside to pull the trashcans to the curb. You’d turned on the lights downstairs on your way out, and as you pass the windows, jogging along the driveway with the cans in tow, you gaze in.

You’ve made a nice home here, modest. The house is red brick with a slate roof. Sturdy. Comfortable. It’s stood here next to its twin since the early-1930s, and from this vantage in the snow, it looks warm, inviting. It provides shelter, safety. But as you near the front porch and glance through the living room windows, this image crumbles.

Through the glass, you spy a figure. It turns the corner from dining to living rooms and dashes upstairs to where your wife is feeding your daughter. It’s only an instant that you see this. It happens in the time it takes to blink. Yet, before you blink again, you’ve released the cans and dashed into the house. The snow crunches beneath your feet. Your shoes slide across the kitchen floor. You leave a trail of print on the carpet as you leap for the landing and bound upstairs. You haven’t bothered to grab a weapon and hope that if the intruder reaches them first, he’ll overlook the hammer.

“Sweetheart!” you cry out.

You cross into the bedroom, and your wife looks up.

“What is it?”

You scan the room, checking corners.

“Have you seen my keys?”

She’s too distracted feeding your daughter to notice you’re out of breath.

“I’m sure they’re around.”

Walking into the hall, you stop at the nursery. You open the closets, but no one’s there. You head outside to check for prints in the snow, but the only tracks are yours.

Is someone really here, hiding?

To leave no prints in the snow, they’d have to have been inside already. Then again, you’re probably seeing things. You have no history of hallucinations and your vision’s 20/20. But in the past two months, you’ve experienced eyestrain from the glare off your computer at work. Blind spots appear in your vision whenever you stare at one thing too long. But this wasn’t a blind spot. This was a person. This was someone standing there. Unless it wasn’t.

It isn’t beyond the realm of possibility that someone could gain access to your home. Lately, in the afternoon, when you bring your daughter in from daycare, you’ve been forgetting to lock the door. It’s surprising, given what’s been going on, but coming home, using one arm to hold the baby in her bulky car seat and the other to prop open the screen, manipulate your key into the outside lock, it sometimes slips your mind to latch the deadbolt once you get inside.

When you bought the house, safety was one consideration among many, but you knew the neighborhood. You’d grown up here. You were moving back to be close to your parents, moving back to send your kids to the schools, moving back because there are parks, pools, places for kids to play. You weren’t bothered at first. Not in the way you’d been in your apartments, in the city. But in the time you’ve lived here, something’s changed. Nothing seems safe. In the local news, you read about people pretending to work for the gas company, people who use this as cover to sneak into houses to steal, so you don’t answer the door unless you’re expecting company.

Part of this has to do with becoming a father. Your daughter was born a year after you’d moved in, and one of the most frightening things is her vulnerability. She’s fragile in every way. Her bones are small, limbs like a bird, soft, weak, helpless. When she was born, you held her in the hospital room, and became, in that instant, her protector. And just as you’ve learned to bask in the joy her presence brings, you’re also wary of what could happen as she grows—those careening cars that veer toward her, hopping the curb and running her down as she learns to ride her bicycle; the strangers at the playground leering, hoping you’ll get distracted so they can steal her away.

It may have been a bad idea to read Helter Skelter when she was three months old. The Manson family saga is enough to leave even the most hardened man lying awake at night, listening for sounds from the windows or doors. Before they broke into Sharon Tate’s house on Cielo Drive and murdered everyone there, they went on practice runs, creepy crawls, they called them. They’d drive around L.A., and pick a house and sneak inside. They’d walk around while the owners slept and move things and then leave without anyone knowing they’d been there.

This incites your paranoia, reminds you of the car, the bear. If the victims had seen it coming, they could have stopped it, fought back. But once the Mason Family entered the grounds on Cielo Drive, it was over, fates sealed.

If only they’d known.

If only they could have prepared.

A week after you chase this phantom figure upstairs, you have a close call with the Hammer and realize it’s time to construct a better plan, conduct a methodical investigation, put your potentially misguided paranoia to rest.

You’re home sick for the day. You woke at two in the morning with a nasty stomach bug. Your eyes opened to pain, and soon you were shivering to such an extent that four blankets couldn’t warm you. There was no time to consider noises in the house, no time to wonder where the person you saw might be hiding. You simply jumped from bed, dashed down the hall, and lost the entirety of the mushroom barley soup you’d made for dinner into the toilet. The sound echoed through the house, waking your wife and daughter, and you stayed up the rest of the night, dry-heaving into a bucket. In the morning, your wife took your daughter to daycare and went to work while you stayed in bed.

Feeling like this, you haven’t given much thought to your intruder. After a quick search online, you’re pretty sure you made him up. You’ve read that even the sanest of people can have hallucinations in situations of sleep deprivation and stress. Yet, your suspicions return when you wake at ten and hear the front door open.

“Honey?” you call. But your voice is cracked, weak. If it’s her, she should have replied. But she hasn’t. “Honey?” you call again. Nothing.

You lift yourself from bed, knees shaking. You haven’t been able to take any food, so you hardly have the strength to support yourself. It’s a prime hallucinatory moment—illness, hunger. Yet, someone could still have broken in. You stand and hear them rummaging around, as if they know that no one’s usually home this time of day. You question whether to hide or confront them. As long as they don’t breach the second floor. That’s where you draw the line. As long as it’s only the first, they can have whatever they want.

You slide down the hall, in stocking feet, silent, stalking. You’ve reached the midway point when it comes—a thunderous rampage of feet, thumping up the stairs. You slide more quickly, your movements hindered by your weakened state. At the landing, you lift the bat, but as you do, your wife rushes past, slams the bathroom door, and begins to make the same ungodly sounds you’d woken the house with hours before. She hadn’t seen you, but you can’t escape the fact that you just missed hitting your wife in the head with a baseball bat by a matter of inches.

As a kid you had nightmares. One of the most frequent concerned sharks. You’d seen Jaws, and it terrified you. Whenever your family took a trip to the lake, your father would sneak underwater and grab your legs and pull a bit, like a shark testing prey. They had explained that sharks live in salt water, but you still had dreams of Great Whites appearing in your local pool or the rivers you went rafting in. You’d imagine submerging and seeing them, their aquiline bodies, cavernous mouths, razor-sharp teeth. They were everywhere, and even when you couldn’t see them, you knew they were waiting, ready to sink their teeth in. You couldn’t bring yourself to swim in the ocean until you reached your teenage years, and even then, you were trepidatious. You didn’t venture too far out. You knew that they weren’t there now, but they existed. The threat was real. Wrong place, wrong time, and they’d take a bite, so you had to be vigilant.

There isn’t anyone hiding in your house. You’re sure of it. Or so you think. The most likely explanation is that you dreamed it, put it together from the strange sounds an old house makes at night, from your fear of someone invading a space that’s supposed to be safe, from an overactive imagination. And since you’d rather not accidentally hit anyone with a baseball bat, you choose an afternoon when your wife’s not at home to conduct a sweep of the house. You refuse to let your paranoia reach the realm of mania, of nervous disorder. And the only way to stop it is to scour every inch of space, to chart the rooms and reassure yourself you’ve imagined it.

You start in the basement and check behind the washer and dryer. The built-in benches along the walls fold back for storage, and as you inspect them, you think of how many places there are to hide. You rummage through the closet with Christmas decorations. You look through boxes, and though you know a full-grown person couldn’t squeeze into them, you need to be methodical. When you’re finished, you can’t have any doubts.

You’re armed with only a flashlight now. You don’t want to risk using the bat. Before you left work, you called your wife to make sure that she was still at the office. But even so, you’re not willing to take a chance. You shine the flashlight behind the hot water heater. A centipede crawling up the wall is the only sign of life you see, and since the basement door to the back steps is bolted, you decide to move upstairs.

As you enter the kitchen, you think of a headline you’d seen in the Times Chronicle last week: Break-in Sends Two to Hospital. You haven’t mentioned your suspicions to anyone, since you’re aware how crazy you sound. But you also know that by voicing them, you might relieve the burden, highlight the absurdity in your thinking. Still, as much as you fear incursion, it also provides a strange kind of fantasy. You picture defending your home.

Break-in Sends Two to Hospital

You’re standing in your living room, confronting two men who’ve broken in, wielding the bat. As the first man charges, you rear back and swing. You hear the crack of his knees as you sweep his legs out from under him. He hits the floor, and you turn to take on the other. You see the fear in his eyes, hear the snap as his jaw breaks and he’s knocked unconscious. There an exhilaration in it. You feel strong, masculine. There’s also that moral certainty that this violence, however extreme, is justified. Of course, the chances it would happen are slim, since you don’t know how to fight. It’s more likely they’d get the best of you. For all the vigilante bluster of your fantasies, the experts’ advice to flee is sensible. You don’t want to hurt anyone unless you’re forced to. Even as you’re having these fantasies, you recognize they’re misguided, some primordial instinct encoded in your genes. And while this drive to violence might have helped your ancestors survive, it has less practical use in modern times. You have intelligence, reason. You try to use these to combat impulses. But some illogical instinct spurs you on. Reason fails. You can’t damp it down with statistics or expert advice. You’re in the dining room now, checking the closet that clicks open every time you enter the house. The one that never shuts properly. The one that makes you jump. There’s too much stuff in here for someone to hide—coats, folding chairs—so you head to the second floor.

The world is full of bad men, scary people, dangerous creatures. The lost sharks of your youth have transformed into burglars, killers, and like those sharks, they lurk in every corner of your mind. It’s up to you to accept they exist, to figure out the odds say they aren’t likely to get you, and move on. Yet, every time you’re alone in the house and reach the foot of the stairs, you experience the certainty that you’ll look up and see a stranger at the top. Your vision zeros in. Your eyes meet. There’s the startling revelation, the rush of terror, fight of flight. But again, as you reach the staircase: no one. No one’s in the bathroom or closet, the back room. No one’s hiding beneath the futon or the baby’s crib or your bed. No one’s dangling from the ceiling like a bat or concealed in the vents like a giant rat, no one’s flashing in and out of existence as they teleport into your home.

There’s one floor left to check, but this has the best places to hide. It’s where you’d hide if you were hoping to avoid detection. You stand in the darkened hall and face yet another set of stairs, stairs to the attic. When you checked the bathroom, you closed the bathroom door; the bedrooms, the bedroom doors; you’ve closed every door behind you to ensure that no one can sneak up on you, but the hall is now dark and the darkness frightens you. The whole house is on lockdown, from the basement up, from the front door to the child gates. You’ve made it so that only a person with intimate knowledge of the layout could move as freely as you. Perhaps even your wife would stumble now and sound the alarm. But she’s still at work. You pause, listen, feel the heft of the flashlight in your hand.

For now, the attic is yours—one elongated finished room with bookshelves, a fireplace, beige carpet, track lighting. When you first toured the house, back when it wasn’t yours, you saw the room with snow falling outside, and thought of how perfect it would be for writing. When you moved in, you spent most of your time up here, working, watching movies, reading books. But since the baby came, you’ve hardly been up here at all. You wouldn’t have noticed someone living behind the walls, and they could be. It’s not as crazy as it sounds. Three access panels, large enough for a person to fit, run along the edge, under the eaves of the roof. Behind the panels, it’s a regular attic, wooden boards with pink insulation foam and space for storage. Pop the panels off, place them back, and one could live here, hidden, emerging only when the house quiets down, when the family leaves, to scavenge.

You place an ear next to the wall and hear nothing. You’ll have to remove the panels one-by-one to be sure. You turn on the flashlight and pop the first. You lean in and shine the light around, but there’s nothing to see, no movement, a few spider webs, the husks of dead insects. You turn to the next and pop it off, but this one’s empty, too.

One more.

It’s good to see no one’s here, to have your suspicions nullified firsthand. You’ve moved to the back of the room, kneeling before the last one. If no one’s here, there’s no one in the house. The car and bear moving were just a misfire of memory; the figure rushing inside, a trick of the light. You pause, listen. A step on the stairs next door. You pop the panel and close your eyes as the floorboards creak. There’s no one here. It’s empty. You’re not sure how they’d get out without you seeing them, but you can’t escape the certainty that right now there’s someone behind you. And you can’t shake the feeling that they mean to do you harm.