Part One: 4:11 p.m.

I have told this story eleven times in official settings and about four times in unofficial ones, and I always start it the same way, because the way it started matters.

It was an ordinary Thursday and I was bored.

That is the honest beginning.

I was fifty-two years old, I had twenty-nine years on, and I had been on the front desk at the Fourth Precinct for four of them because of a back that had stopped tolerating a squad car.

At 4:11 in the afternoon on the ninth of April I was halfway through a parking complaint from a man who had called us three times about the same vehicle, and I was thinking about what I was going to eat.

The lobby smelled the way it always smelled, which is burnt coffee and wet coats.

There was a box fan on the file cabinet because the building’s air handling had been broken since February.

Rain on the glass.

The outer doors opened and two little girls came in holding hands.

They were seven.

I know that now; at the time I would have guessed six or eight.

They were dressed identically in gray hooded sweatshirts and jeans, both soaked through, neither of them wearing a coat, and their sneakers were making the sound wet sneakers make on that tile.

One of them was walking normally.

The other one was folding — every four or five steps she would bend at the waist and stop, and the first one would stop with her and wait, and then they would start again.

I stood up.

My chair rolled back and hit the cabinet behind me, which I remember because the noise made the second girl flinch hard.

“Hey.