For a minute I just stand there, the piece of paper shivering in the sea breeze, trying to understand what this means. Was it Luc? But I can’t believe that he would do such a thing, he loved Kate. Was it Kate herself? Impossible though it seems, I can believe that more easily.

I am still standing there, trying to work out the mystery of this hate-filled little thing, when there is a gust of wind, and the curtain flaps, and the piece of paper falls from my fingers. I snatch for it, but the wind has caught it, and all I can do is watch as it flutters towards the Reach and sinks into the milky, muddy water.

Whatever it was, whatever it meant, it’s gone. And as I turn for bed, shivering a little in spite of the warm night, I can’t help thinking – perhaps it’s for the best.

I SHOULD BE tired enough to sleep well, but I don’t. I fall asleep with the scratched-out face in my mind, but when I dream, it’s of Salten House, of the long corridors and winding stairs, and the endless search for rooms I couldn’t find, places that didn’t exist. In my dreams I’m following the others down corridor after corridor, and I hear Kate’s voice up ahead, It’s this way … nearly there! And Fatima’s plaintive cry after her: You’re lying again …

At some point Shadow wakes and barks, and I hear a shushing voice, footsteps, the sound of a door – Kate is putting the dog out.

And then, silence. Or as near to silence as this old, ghost-ridden house ever gets, with its restless creaking resistance against the forces of winds and tides.

When I wake again, it’s to the sound of voices outside, sharp whispers of concern, and I sit up, bleary and confused. It’s morning, the sun filtering through the thin curtains, and Freya is stirring sleepily in a pool of sunshine next to me. When she squawks I pick her up and feed her, but the voices outside are distracting both of us. She keeps raising her head to look around, wondering at the strange room and the strange quality of light – so different to the dusty yellow sunshine that streams into our London flat on summer afternoons. This is a clear, bright light – painful on the eyes and full of movement from the river, and it dances on the ceiling and walls in little pools and patches.

And all the time the voices … quiet, worried voices, with Shadow whining unhappily beneath like a musical counterpoint.

At last I give up, and I wrap Freya in her comforter, and me in my dressing gown, and head downstairs, my bare feet gripping the worn wooden slats of the stairs. The door to the shore side of the Mill is open, and sunlight streams in, but I know before I have even turned the corner of the stairs that something is wrong. There is blood on the stone floor.

I stop at the curve of the stairs, holding Freya hard against my thumping heart, as if she can still the painful banging. I don’t realise how hard I am holding her, until she gives a squeak of protest, and I realise that my fingers are digging into her soft, chubby thighs. I force my fingers to relax, and my feet to follow the staircase to the flagged ground floor, where the bloodstains are.

As I get closer I can see they aren’t random droplets, as I’d thought from the top of the stairs, but paw prints. Shadow’s paw prints. They come inside the front door, circle, and then go swiftly out again as if someone had shooed the dog back outside.

The voices are coming from the land side of the Mill, and I shove my feet into my sandals and walk, blinking into the sunshine.

Outside, Kate and Fatima are standing with their backs to me, Shadow sitting at Kate’s side, still whimpering unhappily. He is on a lead, for the first time since I got here, a very short lead, held tightly in Kate’s lean hand.

‘What’s happened?’ I say nervously, and they turn to look at me, and then Kate stands back, and I see what their bodies have sheltered from my gaze until now.

I inhale sharply, and I clap my free hand over my mouth. When I do manage to speak, my voice shakes a little.

‘Oh my God. Is it … dead?’

It’s not just the sight – I’ve seen death before – it’s the shock, the unexpectedness, the contrast of the bloody mess before us with the blue-and-gold glory of the summer morning. The wool is wet, the high tide must have soaked the body, and now the blood drips slowly through the black slats of the walkway into the muddy shallows. The tide is out, and only puddles of water remain, and the blood is enough to stain them rust-red.

Fatima nods grimly. She has put her headscarf on again to go outside, and she looks like the thirty-something doctor she is, not the schoolgirl of last night.

‘Very dead.’

‘Is it – was it …’ I trail off, not sure how to put it, but my eyes go to Shadow. There is blood on his muzzle, and he whines again as a fly settles on it, and he shivers it off and then licks at the stickiness with his long pink tongue.

Kate shrugs. Her face is grim.

‘I don’t know. I can’t believe it – he’s never harmed a fly, but he is … well, capable. He’s strong enough.’

‘But how?’ But even as the words leave my mouth, my gaze travels across the wooden walkway to the fenced-off section of shore that marks the entrance to the Mill. The gate is open. ‘Shit.’

‘Quite. I’d never have let him out if I’d realised.’

‘Oh God, Kate, I’m so sorry. Thea must have –’

‘Thea must have what?’ There’s a sleepy voice from behind us, and I turn to see Thea squinting in the bright sunlight, her hair tousled, an unlit Sobranie in her fingers.

Oh God.

‘Thea, I didn’t mean –’ I stop, shift uncomfortably, but it’s true, however my words sounded, I wasn’t trying to blame her, just work out how it happened. Then she sees the bloody mess of torn flesh and wool in front of us.

‘Fuck. What happened? What’s it got to do with me?’

‘Someone left the gate open,’ I say unhappily, ‘but I didn’t mean –’

‘It doesn’t matter who left the gate open,’ Kate breaks in sharply. ‘It was my fault for not checking it was closed before I put Shadow out.’

‘Your dog did that?’ Thea’s face is pale, and she takes an involuntary step back, away from Shadow, and his bloodied muzzle. ‘Oh my God.’

‘We don’t know that,’ Kate says, very terse. But Fatima’s face is worried, and I know she is thinking the same thing I am; if not Shadow, then who?

‘Come on,’ Kate says at last, and she turns, a cloud of flies rising up from the dead sheep’s guts, splattered across the wooden jetty, and then settling back to their feast once more. ‘Let’s get inside, I’ll phone round the farmers, find out who’s lost a ewe. Fuck. This is the last thing we need.’

And I know what she means. It’s not just the sheep, coming as it does on top of our hangovers and too little sleep, it’s everything. It’s the smell in the air. The water lapping at our feet, that is no longer a friend, but polluted with blood. The feeling of death closing in on the Mill.

It takes four or five calls for Kate to find the farmer who owns the sheep, and then we wait, sipping coffee, and trying to ignore the buzzing of the flies outside the closed shore door. Thea has gone back to bed, and Fatima and I distract ourselves with Freya, cutting up toast for her to play with, although she doesn’t really eat, just gums it.

Kate paces the room, restlessly, like a caged tiger, walking from the windows overlooking the Reach, to the foot of the stairs, and then back, again and again. She is smoking, the rippling smoke from the roll-up the only sign of fingers that are shaking a little.

Suddenly her head goes up, for all the world like a dog herself, and a moment later I hear what she already did: the sound of tyres in the lane. Kate turns abruptly and goes outside, shutting the door of the Mill behind her. Through the wood I hear voices, one deep and full of frustration, the other Kate’s, low and apologetic.

‘I’m sorry,’ I hear, and then, ‘… the police?’

‘Do you think we should go out?’ Fatima asks uneasily.

‘I don’t know.’ I find I am twisting my fingers in the hem of my dressing gown. ‘He doesn’t sound exactly angry … do you think we should let Kate handle it?’