The water cascades over my body in a gentle stream, an attempt to wash away the disaster that my life has become. I stare at the gathering droplets on the shower screen wishing I could become one of them – a single, innocuous bead of water. I focus my gaze on one, then smear it away with my fingertip. Gone. Disappeared. It’s thoughts like these which have driven away my husband. My fingers curl into loose fists. I flex them, wincing at the painful pull of scratched, bruised skin on the back of my hand.

Dom has gone to his parents’ house. He’s taken our daughter with him, and I’m here alone in this house that has become more like a self-made fortress, a prison. Turning my face up to the shower head, I close my eyes and stand, unmoving, letting the water flow. For how long, I don’t know. Eventually, my mind clears a little and the dark thoughts recede to be replaced by a small flutter of determination.

The shower dial creaks as I switch it off. I push open the steamed-up cubicle and step out onto the mat. A damp towel hangs on the back of the door. I use it to dry myself, carefully patting the livid bruises, and then I go into the bedroom and pull on a cotton sundress – one that’s loose enough not to irritate my tender skin.

Downstairs, I drink more water, determined to flush any toxins out of my body. I’ve already poured two boobs’ worth of milk down the sink, but I don’t know how much more I’ll need to ditch until it’s safe for Daisy to drink again. Just thinking about her gives me a physical ache in my chest. I bend forward with my hands on my hips, sucking in breaths to ease the hurt. Will she be crying for me? Surely she’ll be missing her mummy? I dread to think what Dom has told Geoff and Audrey. They’ve always spoiled Dom, so they’ll take his side, no questions asked. I get on with his parents, I love them, of course I do, but when it comes down to it, he’s their son and they will happily believe the worst of me. Of that I’m quite sure.

I pour myself another glass of water and drift into the lounge, but I’m too restless to sit. Instead, I stand and stare out of the window, at the stillness of the cul-de-sac. It’s Sunday, so the builders aren’t around. Nobody’s around. I glower across at Mel’s house, unsure if our friendship will ever recover from this. Why did she text Dom rather than me? I think she must still bear a grudge about the money. I sigh. Perhaps I was too judgemental, too harsh. Maybe I should have given her the money gracefully without any demands. After all, she’s like family. But I can’t think about that now. I have more important things to worry about, like the state of my marriage, and when Dom is going to bring Daisy home.

It’s funny, but without Daisy here, I don’t even feel an urge to check the locks. What’s the point? Maybe it’s a good thing she’s at Dom’s parents. She’s safer away from home because, although Geoff and Audrey’s house is only a few minutes’ drive away, at least Martin doesn’t know where they live.

I notice that my neighbour’s car is missing from his driveway. My heart thumps uncomfortably as I realise what this means… Martin is out. But when did he leave and when is he coming back? I don’t know the answers to those questions, which means he could be back any minute. Do I dare to do what I know needs to be done? Couldn’t this be the perfect opportunity, while Daisy is out of the house? I still don’t feel as though I’m quite in my right mind. My thoughts are scattered and shaky. But what I do know is that I won’t be able to relax until I see who or what is down in Martin’s basement. I need to prove to myself that I’m not losing my mind, that something really is going on next door. And, if I’m honest, I have a strong urge to prove Dom wrong. To say I told you so.

I scoop up my shoulder bag from the sofa and slide my phone inside. I decide to go out the back way in case any neighbours are looking out of their windows. I ease the back doors open and step outside, scanning the garden and the fields beyond. No movement. Nothing but patchy grass, trees and sky. Gripping the heavy wooden patio table with both hands, I heave it off the flagstones and onto the grass. From there, I drag it over to Martin’s fence, churning up the dry grass and leaving two parallel gouges across the lawn.

Nervously, I glance around once more, but I’m still too close to the house for the Parkfields to spot me from their windows, unless they decided to lean out for some reason. My side is throbbing with pain again, but I ignore it. What I’m doing now is more important than any physical discomfort I might feel. I clamber up onto the table. Kneeling, I hold my breath and peer over Martin’s fence. His garden appears to be empty. All the while I have one ear cocked for the sound of an engine or car door slamming, but so far, all is quiet.

Okay, this is the point of no return. I’m about to break the law.

Gingerly, I grip the top of the fence and wiggle it, testing its strength. Our side of the fence is grey and faded, but Martin’s side has been coated with wood-preservative and it feels strong enough. With shaky limbs, I swing one leg over, then the next, and drop down into his garden. My whole body jars, and it’s all I can do to stop myself from crying out as the pain in my right side flares. With watering eyes, I stand for a moment and wait for the feeling to subside a little. But time is not on my side – Martin could be back at any moment.

I scan the back of his house for an open window, but there are none, so I scoot around the side where there are two frosted-glass windows, both shut. The only options open to me are to either go back home and forget this, or to break into Martin’s house.

I’ve come this far, I can’t back down now.

All of Martin’s windows are double glazed, impossible for me to break, but his back door is half-glazed with what looks like a single pane of opaque glass. A large stone would do the trick, and then I could reach in and hope that the key is in the lock. I glance around the garden, searching for anything suitable to use. By my feet, I see a metal trowel in an empty plant pot. I pick it up. The handle is solid metal. A hard jab on the door pane should be enough to break it. I realise I’m biting my bottom lip so hard that I can taste blood.

Creeping over to the back door, I test the handle, just in case. To my utter amazement, the door opens. I almost drop the trowel in shock. Could Martin actually have gone out without locking his back door? It doesn’t seem very likely. Does that mean he’s at home despite his car not being here? My heart twangs. What should I do? What should I do?

‘Hello?’ I murmur through the open door, tensing up. If Martin is in, I can simply say I saw someone snooping around, and came over to check. Then, I’ll make my excuses and get the hell out of here. ‘Hello?’ louder this time. I walk into the kitchen, my whole body on alert. ‘Martin!’

Nothing. Not a creak or a sigh.

Okay, well, I’m in here now. I set the trowel down on the kitchen counter and step into the hall, the stench of air freshener assaulting my nose, throat and lungs. I walk past the basement door, heading towards the bottom of the stairs. I stare up, convinced Martin will be standing at the top, a look of outrage on his face. But the landing is empty, a dark space. I force myself to call up one more time. ‘Hello?’ I wait, frozen…

Nothing.

Before I go down to the basement, I peer into the lounge and out through the net curtains. His car is still not back. Good. Okay. I return to the basement door, take a breath, and pull it open. What am I going to find down here?

There’s a light switch on the wall which I press, illuminating a newish-looking wooden staircase. At the bottom lies another door with key sticking out of the lock. What is behind that door, and why does it need a lock? I give a shiver. My fingers are shaking. I check that I still have my bag over my shoulder with my phone inside, in case I need to call the police. Yes.

I can’t put it off any longer. I have to go down there. The blood whooshes in my ears as I put one foot on the first step, then my other on the next. Soon I’m halfway down and I throw a panicked glance up over my shoulder, listening out for footsteps above me. All I hear is my own breathing, amplified in the narrow space.

I take the final few steps to the bottom and stand in the small uncarpeted area before an innocuous, veneered wooden door. Despite the air being cooler down here, I feel sticky and short of breath, like the walls are closing in. I grasp the key and try to turn it while throwing glances behind me up the staircase. Down here, I’m vulnerable. I wonder if I would even be able to get a phone signal if I needed to. The key doesn’t turn, but I realise that’s because the door is already unlocked. So I press down on the handle and push open the door.

‘Kirstie? Is that you?’

I whimper, frozen in place.

He’s standing there behind the door, a puzzled expression on his face. ‘What are you doing down here?’ Martin asks, his frown turning into a half-smile.