Beth’s skin crawls. She wants to be sick. She reaches for the antiseptic wipes. ‘I’m fine, darling,’ she whispers to Martha, trying to lower the mask that has served her so well over the years. But it stalls as the image of Saskia’s WhatsApp message flickers behind her eyes. Who the hell is Kat, and why did she say she knew Beth eighteen years ago?

‘How was Santa?’ she asks, desperate to buy time, to work out how to function around her family. Beth watches her eldest daughter’s lips move, but she doesn’t hear the words. Her head is too dense. Her life swerved eighteen years ago when Eddie died. Her fear of dirt and germs escalated so much that life became unbearable. She was sent to that place, the mental health unit. Dr Sharp gave her tools to cope – medication first, then CBT – and she worked out some strategies of her own. But the memory of being there is still shameful. Living amongst such hopelessness.

She spent five months in the unit, eighteen years ago. Did Kat know her in that place? Beth squeezes her eyes shut and tries to position Kat’s face next to her shrouded memories from that time. But there’s nothing.

Perhaps Kat knew her before she left home. Or more accurately, knew of her. Yes, that makes more sense.

In the article that the local newspaper ran when Eddie died, they wrote lots about his poor, struggling family, including a photo of the tiny bedroom she and Eddie shared. Suddenly everyone in the local area knew how she lived. Some felt sorry for her, others looked away, but most people wanted to know more. To get closer to the drama. That’s why Saskia’s MyNeighbour post was so excruciating: the threat of history repeating itself. Kat could be any one of those voyeurs from years ago. A girl from school, or just someone who read page three of the Berkshire Gazette that week.

Except would someone like that really recognise Beth after all these years?

And why would she want to be part of Beth’s life now?

Kat has been in her home, Beth realises with another wave of nausea, alone with her children. She found her in Martha’s bedroom on Thursday morning when she was still groggy from sedatives. Beth thinks about finding her wardrobe door askew when she got home yesterday.

Is it Kat who’s been riffling through her things rather than Mark? And if it is, how hard did she look? Did she find Beth’s pills? Or the bag with Eddie’s most precious possessions? Beth gave him the Zippo lighter to convince him to give up the smack. The engraving – Please fucking stop – cost an extra ten pounds but she thought it was money well spent at the time. A dose of guilt with every hit. But guilt requires caring, she realises now, and Eddie was long past that.