They don’t speak again during the five-minute walk to school. There’s enough chatter from the children for it not to appear too awkward but Kat doesn’t care anyway; the less comfortable Saskia is, the better she feels. All four children race into school as soon as they arrive, and Saskia makes some excuse about a barre class and scuttles off. With a new level of hope rocking in her tummy, Kat looks at the unfamiliar door key in her hand and starts back down the hill.

Luna is asleep in her daybed when Kat walks inside, and the house is silent. She breathes in the now familiar smell – a mix of bleach and cedarwood diffuser – and wonders where to go first. She knows that Beth could wake up at any moment, and that she’ll need to explain herself when that happens, but her urge to search, to discover, is too strong for that risk to hold her back.

She doesn’t bother with the playroom, and the study turns out to be full of Simon’s work stuff. A few books on the shelf, but mainly wires and cables snaking up from plug sockets and two big screens sat angled on the desk. The kitchen is clearly Beth’s domain, but it doesn’t reveal much either. Beth still craves cleanliness and order, but Kat had worked that out on Tuesday evening. There are half a dozen expensive hand creams under the sink and Kat rubs some Clarins lotion between her palms. She inhales its citrusy perfume – so different to the medical creams she’s used to – and wonders if she’s brave enough to go upstairs. Being found perched on a bar stool in Beth’s kitchen is one thing; being caught lurking around bedrooms is quite another.

But there might be something interesting up there.

Kat saw windows in the roof, which means there’s a loft bedroom, or more likely a full-on suite with wet room and walk-in cupboards. She’s sure that’s where Beth will be. Which means she can risk checking out the first floor. Carefully, silently, she climbs the stairs. Her heart is thudding when she reaches the top, but the stillness around her calms it. The bedroom door to her right is adorned with multi-coloured wooden letters spelling MARTHA. She gently pushes on the door and slips inside.