The office was on the Lower East Side, above a laundromat that smelled of chemicals and desperation, and it contained exactly three pieces of furniture that worked: a desk with one leg shorter than the others (I stuffed a matchbook under it), a chair that squeaked when you sat in it (I stopped sitting in it), and a filing cabinet with three drawers (the third one stuck, which was fitting, because the files inside were the ones I preferred to forget). It was October 1929, and I had three dollars in my pocket and a bottle of bourbon on the desk that I told myself was for sanitary purposes.

The sign on my door says Morano Investigation Services. Below that it says Honest Prices, Honest Work. That is a lie. I am not honest, and the work is not honest. But it is work, and in New York, work is the closest thing most people get to prayer.

She walked in at half three, wearing black the way a confident person wears confidence—as something natural and unremarkable. Twenty-eight, maybe, with eyes that were red but not from crying. From sadness. From resolve. There is a difference. Sadness makes you soft. Resolve makes you dangerous.

My name is Dorothy Lansing, she said. My husband died a month ago. The police say he jumped. I do not believe him. I want to know why he could not live.

Why come to me? I asked. I am not exactly the first name on anyone's list.

Because you were a cop. And because they think you are guilty too.

I wanted to refuse. I have learned over the years that the people who walk into your office with resolve usually have money, and the people who have money usually have lies. But something caught my eye when she shifted her handbag on her lap: a corner of paper sticking out, with handwriting I recognized. I had seen those names before. Eight years ago, when I was still a detective with the NYPD and still believed that the badge meant something other than a target on your back.

The names were on William Lansing's notes. My former partner's name was circled in red.

I took the case. Not for the money. For the names.

William Lansing's apartment was in Midtown, a fourth-floor walk-up with peeling paint and a super who charged extra for heat in November. I found a hidden drawer beneath the floorboard in the closet—nobody builds a house without hidden drawers anymore, it is as natural as hiding something under the mattress. Inside the drawer was a photograph. Three men and William, smiling in front of a restaurant on Washington Square. One of them was Senator Edward Harlowe, a political operator whose smile could open doors that did not want to be opened. The second was a man I knew—a former police colleague who was reported dead by suicide three years ago. I had attended the funeral. I had not believed the suicide note.

The first lead took me to Harlem. Ava St. Clair owns three speakeasies in Harlem and knows everyone who walks through their doors. She is thirty-five, built like a woman who has spent her life fighting for everything she owns and winning most of those fights. Her place on 135th Street was full of jazz and smoke and people who carried secrets the way other people carry wallets.

Ava knew William, she told me. She poured me a drink that was probably not legal and probably not whiskey. He was looking into a big corruption network. He said he had evidence. Then he died. She gave me a slip of paper with a phone number and a time. Find this person. But be careful. Someone is watching you.

The number led me to a warehouse in the Bronx and a man named Mike—Red Mike, because of the scar on his left cheek and the nervous energy of someone who has run out of places to hide. He would not talk at first. I gave him five dollars and a promise of protection. Men like Red Mike do not need much incentive. Five dollars in 1929 is three days of rent for some people. A promise is almost as good as money, if you are desperate enough.

Harlowe's campaign manager, Vincent Cole. That was the name. Cole lived in a luxury apartment on Fifth Avenue that made my suit feel like a costume. He was not afraid of me. He smiled when I told him who I was. You are playing a game bigger than you are, Morano. But you are a brave fool. That is charming, in a way.

When I got back to my apartment, someone had been through my things. Nothing was missing. Everything was moved. A message, not a robbery.

Dimitri Voss met me at a coffee shop on Delancey that stayed open twenty-four hours because some neighborhoods do not know how to sleep. He was thirty-four, Greek-American, tall, quiet—the kind of man who says little and means every word. My former partner. The only cop I still trusted. Or tried to.

Some things are better left unknown, he said. His eyes were tired. Not the tired of a long shift. The tired of a long life.

I already know some things. The question is what I can do about it.

He was silent for a long time. Eight years ago, they told me to shut up or lose the badge. I chose to shut up. Every day, I regret it.

I found William's last note. Seven names. Seven corrupt cops. Each one represented a different kind of rot. The first took small bribes from street vendors. The second used torture to extract confessions. The third sold information to organized crime. The fourth through sixth covered political connections, judicial manipulation, community intimidation.

The seventh name was Dimitri's.

I did not believe it. I went to Dimitri. He admitted it—not that he was corrupt, but that he knew things and said nothing. My daughter, he said quietly. They threatened to hurt her.

Ava was attacked on a Tuesday. I got the call at three in the morning. Her speakeasy on 135th Street was burned to the frame. But Ava was not there. She was in a safe apartment in Brooklyn, with a wound on her arm that looked like a knife but could have been a pipe. They were looking for information about William, she said. I do not know anything. But they do not believe me.

I looked at Ava's wound and felt something I had not felt in years. Not anger. Anger is expensive. This was colder, cheaper, more durable. Certainty. These people have to stop. Not because of justice—justice is a luxury I gave up eight years ago. But because it is the only thing left that makes sense.

I compiled the evidence on all seven men. It was enough—if I could give it to the right people. But the question was: who are the right people? The system is the problem. You cannot ask the system to fix itself the way you cannot ask a drowning man to save you.

So I did what I could not do as a cop. I wrote the file. Not to the Police Department. To the newspapers—the New York Times, the New Yorker. Dorothy helped, connecting me through her legal contacts. She had William's original notes. Ava provided the black market records. Dimitri provided internal information, on the condition of anonymity.

The file ran. The headlines were explosive. Senator Harlowe resigned. Seven cops under investigation. The system cracked—not collapsed, cracked. A hairline fracture in a wall that has been holding up a house full of bad men.

Dimitri resigned from the force and left New York. I cannot look at my children and answer their question about whether police are good men, he said. Ava lost her speakeasy but opened a legitimate restaurant with the settlement money. Dorothy left—not from fear, but because she was done. You did what William wanted to do, she said. Now I am going to do what I want to do.

I walked back to my office. The desk with the short leg. The chair that squeaks. The filing cabinet with the stuck drawer. On the desk: a glass of bourbon, a telephone that might ring with another case, another person in another room of this city who needs someone willing to look at the darkness and not look away.

I picked up the glass. I put on my coat. I took the umbrella by the door and walked out.

The night is still dark. But a man can light a lamp. Maybe not enough to see the whole street. Just enough to see the next step.

In New York, that is all anyone can ask for.