Embroidered pictures of flowers line the main wall of the conservatory. At the far end, a circular table with a lace tablecloth, and four chairs around it, looks as though it’s never used. A shelf laden with books, jigsaw puzzles, and board games is closer to me, next to a sofa that would seat six, with expensive throws covering worn upholstery. My eyes fall on a grey cat curled up on an armchair, silently sleeping. Someone must be here. Michael? His daughter Julia, perhaps?

Flashes of memory of Julia arriving in her yellow sports car at the same time as the police the day after Lark and Jackson disappeared invade my mind as I continue through the door into the main house.

‘Rosamund,’ I call. ‘Rosamund?’

The hallway has several doors leading from it, and there’s a staircase to the first floor. I pull off my woolly hat and scarf. It’s warm in here – the central heating pumping out dry heat. ‘Hello!’

I make my way into a dual-aspect room. It’s the room I saw through the window at the front of the house.

I’m drawn to a heavy oak unit where framed photographs are on display.

There are pictures of Julia in her graduation gown, and several of Michael Collis. I know it’s him. I looked him up online after Lark disappeared – though I never met him. He’d inherited the Drummondale House estate from his parents when he was in his thirties, almost thirty years ago. He’s an attractive man with grey hair and ice-blue eyes, and there’s a confidence about the way he stands, shoulders back, a crystal glass in his hand in almost every photo.

My eyes skitter over the faces in the pictures, landing on a large photo of a young girl of around fifteen. I pick it up. I’ve seen this girl before.

I go to place the photo back on the dresser, but something distracts me. There’s movement outside, and I step towards the back window.

I gasp, and the photo slips through my fingers and lands with a thud on the patterned carpet. Someone, wearing the mask we saw earlier, is peering over the high garden wall. A chill runs down my spine as I step backwards, my heart racing. My stomach tight with fear, I spin round and race towards the door and fling it open. But before I leave I take a deep breath and turn back towards the window. Whoever it was out there in the snow has gone.

‘Rosamund,’ I cry, once I’m back in the hallway. ‘Rosamund, where are you?’

Seconds later, the door to another downstairs room opens and Julia Collis appears, removing ear buds from her ears. She’s dressed in a beige leotard and thick black tights. Looks slimmer than the last time I saw her.

‘What the hell are you doing in my father’s house? You totally messed up my meditation.’