So I talk to Meddie, too. My abiding fear is that Peter will try to hurt her again, sooner or later: he won’t be able to help himself. And Meddie knows this as well as I do, which means I’m afraid for my son, too. She’s smarter than Peter, older and stronger. Unlike him, she has guile and the ability to control her temper. Peter doesn’t scare her.

In our house, Tom is the only one who’s afraid.

And then I do what anyone struggling to keep the peace between warring factions does to unite them: I find them a common enemy.

I ground them both, take away their screens, and force them to spend the long summer days sorting through clothes and toys and books in their bedrooms in preparation for our move next month. They’re both so furious with me, they forget to be angry with each other.

But I know the detente won’t last.

I untangle the bedding on the floor now and get into bed, floating the sheet across us both and settling back against the pillows. I pick up my book, but I’m too tense to read. I don’t know what more I can do to keep my family safe. My father was right: I should never have been allowed to have children. Tom is a good man: I’d always hoped his genes would win out over mine, but clearly that’s not the case with our son. Poor Tom.

Peter has known nothing but love. Neither of us have ever raised a hand to him, not even to slap his fingers away from a hot stove. I have to hope it’s not too late for him. I managed to channel the liabilities of my personality into an arena where they became assets: my inability to connect emotionally with my patients and feel their fear is what enables me to stay cool under pressure and save their lives. I have to believe I can help Peter do the same.

Maybe moving to a new house will give us all a new start. I know I’m pinning too much on the idea, but what else do I have?

Tom switches off his bedside light and turns towards me. His bare torso is gilded amber by the streetlight outside. He’s been working out, I realise suddenly: he has the sharply defined abs of an Olympic swimmer.

‘Millie, you’ve got to let this thing with Peter go,’ he says, taking the unread book from my hand. ‘He’s got some problems, we know that, but he hasn’t inherited some sort of “bad seed” from you. What happened with your father wasn’t your fault. You’re not a bad person. If you wanted to, you’d be perfectly placed to kill dozens of people without anyone ever knowing, but you go into that hospital and save lives every day.’