She manages a nod. ‘Yes, I just… for a minute there I thought something had happened to Rob.’ She straightens up. ‘What’s your name?’

It doesn’t escape Sienna’s notice that she hasn’t mentioned Abby, that her only concern is for her son. She holds out her hand. ‘Sienna Wells.’ She waits for recognition to dawn; surely Abby would have mentioned her after all the time they’ve spent together since she moved to London.

Rob’s mother reaches forward, her handshake firm. ‘Oh. Rob’s never mentioned you.’

‘I’m more a friend of Abby’s actually.’

This is when it happens; all the warmth drains from her face and her eyes harden. There’s something there, something off between Rob’s mother and Abby. If she’s right, then this can only help her. ‘So something’s happened to Abby?’ the woman is saying. She frowns. ‘Rob would have told me.’ There is no concern in her voice, just curiosity.

‘It’s not that. It’s… a bit complicated actually.’

‘You’re going to have to give me more than that,’ she says.

Standing here in front of this woman, Sienna can tell she is fierce, and that to get her to listen she will have to be bold. No nonsense, no games. ‘My husband Greg’s gone missing, and I think Abby might have something to do with it.’ There. She’s said it now. There is no going back. ‘Let me show you something. To prove I know Rob and Abby.’ She pulls out her phone and scrolls through her photos until she finds one of the four of them together. A selfie, taken at Abby’s house one evening. Sienna remembers how nobody had been thrilled to have it taken; now she’s glad she persisted. She holds the phone up for Rob’s mother to see.

She only looks at it for a second. ‘I think you’d better come in. I’m Lillian by the way.’

This is all it takes to get through Lillian Nichols’s door, and moments later Sienna is led out to the back garden. ‘It’s too nice out to sit inside,’ Lillian says.

‘Can I get you something to drink?’ she offers as they sit at her large garden table. Everything out here is tidy, the garden beautifully landscaped, reinforcing the idea Sienna has already formed that Lillian is a perfectionist. Someone who needs to be in control. All of this can only help her.

‘No, thank you. You’re already giving me your time, please don’t go to any more trouble.’

‘It’s no trouble. I’m intrigued to hear what you’ve come here to say.’

‘Really, I’m okay.’

‘Well, I’m getting myself some water, so I’ll be back in a moment.’