My wife was four hours late coming home and her phone went straight to voicemail, so I checked her location on our tracking app — but when I drove there and saw what she was doing, I completely forgot how to breathe.

Sorcha is a paediatric nurse.

Her shifts are long and she is the most reliable person I have ever met.

Yesterday morning she kissed my cheek at the door. “Home by quarter past seven. I’ll get Thai on the way. Love you.”

And we have one rule in thirteen years, which is that if she is going to be late she texts.

And by eleven o’clock last night she was four hours late and her phone was going straight to voicemail.

I did not panic straight away. I rang the ward first.

“She clocked off dead on seven,” the charge nurse said. “Said she was going straight home.”

I rang her sister. I rang two of her friends. I rang the police, and a dispatcher told me, not unkindly, that unless there was a documented medical emergency I had to wait twenty-four hours.

And that is when my hands started doing something.

So I opened the tracking app.

And her dot was sitting completely still at an address I did not know, out past the retail park, on Kesteven Way.

I got in the car.

Her SUV was parked round the back of a dark building with no sign on it. There was a heavy metal door propped open with a fire extinguisher and a strip of hard white light coming out onto the concrete.

And I went up to that door expecting to find her hurt, or to find her with somebody.

And her phone was on a metal folding table just inside, switched off. Properly off, not on silent.

And she was completely fine.

And what she was doing in the middle of that room stopped everything in my chest.

There was a girl of about eight on a table.

And my wife was doing her hair.

She had a comb and a brush and a small bottle of something, and she was plaiting it, and then she was taking it out and starting again.

I watched her do it four times.

Four times, in about twenty minutes, at half past eleven at night, on her own, under a strip light, in a building with no name on it.

Because it was not right.

That was all. She could not get it right, and she would not leave it, and every time it came out wrong she took the band off and combed it through and started at the top again.

And on the fourth one she stopped and put both hands flat on the table and stood there for a while.

And then she did it a fifth time.

And I want to put down the four hours before that, because they are the reason I was in that car park at all and because I was not a good man in them.

Between seven and eleven I was fine.

She is late sometimes. I made Rosa’s tea and did bath and read her two chapters and put a wash on.

At about half nine I texted and got nothing and thought nothing of it.

At about half ten I started making a face at my own phone.