I know what it takes to make it through the kind of childhood she had, because I know what Millie had to do to make it through hers.

Harper’s learned how to make hard choices. She’s aware the world’s a cold, unforgiving place, and that life is nasty, brutish and short. The weakest in the herd are picked off: only the fittest survive.

Kill or be killed.

‘Look around you,’ I say gently. ‘In a few weeks, this house will be yours. You did this. You’ve come a long way from the back seat of a car.’

Her eyes are bright. ‘Thank you for saying that.’

I hope Millie can find it in her heart to be kind to this girl. Compassion’s not her strongest suit: it’s hard to show kindness when you’ve never experienced it yourself. And for some reason my wife is fixated on the woman on the other side of our housing chain: Stacey Porter.

I don’t know what it is about her that presses Millie’s buttons, but every time my wife mentions her name, I get nervous.

chapter 15

millie

I hear voices coming from the kitchen as soon as I walk into the house.

Annoyed, I hang my keys neatly on the hook, and put my sunglasses back in their case on the hall console.

Tom knows I’ve been on my feet in theatre for close to thirty hours. I’ve rehearsed for today’s procedure – the separation of eighteen-month-old conjoined twins – for close to four months: the surgery has been on my calendar for weeks now. I don’t normally operate on paediatric patients, but the team handling the separation were unable to find a paediatric cardiac surgeon sufficiently skilled to take on the case. Successful separation of twins with a thoraco-omphalopagus connection is extremely rare for obvious reasons: you can’t divide a heart in two the way you can a liver. The girls shared a connection at the atrium, the upper chamber of the heart, close to several vital veins. The chance both babies would die during surgery was almost one hundred percent: no rational surgeon wants to take on those odds.

Which is why the team came to me.

I used cardiac CT and MRI scans from both before and after the twins were born to create a 3D printed model of their heart, which allowed me to examine the shared structures and meticulously plan how to separate them. I spent weeks experimenting with different options until I found the 0.001 percent chance that’d give both girls a shot.

I rarely get nervous about my cases, but for some reason this one got to me. It’s why I needed the therapy of drifting through a stranger’s house after successfully keeping my addiction in check for so long.

But my efforts paid off. The girls didn’t die on my table.