Life is a test, and the final grade is always an F.

THAT YEAR I HAD a black key made for the front door. Except for the color it looked like a regular key, but it also contained an electronic component. The physical device did indeed turn a mechanical lock, but the electronics flipped another switch throwing back a bolt that came up through the floor. The door itself was reinforced with a titanium plate.

In a drawer in my office I had a few key rings that had masters for almost every lock in New York City. And for those that were "unique" I had illegal masters that were able to adjust to the cylinders they encountered.

Just because I was aware of dangers that other people were ignorant of didn't make me paranoid. I didn't feel bad about having the locks on my front door changed at least once a year.

My enemies would have to work to get at me or mine.

BECAUSE THE LOCK IS always new it didn't make much noise. I was halfway down the hall to the dining room when I heard the voices.

It was a man and Katrina speaking in normal tones. There was no urgency or conflict there-no feeling.

"Dimitri?" Katrina called. "Dimitri, is that you?"

"It's me, Katrina," I said and then I entered through the open door.

My wife was sitting at her end of the rustic hickory-wood dining table and a man somewhere in his late thirties was sitting on the side, a place away from her. They both had teacups in front of them.

He was a brown man with straight dark hair and a small, Caucasian nose. His face was too boyish to be called handsome or plain. His eyes were brown also and more mature than the rest of his physiognomy.

"Leonid," my wife said.

She stood and walked toward me, past the pickle jar of wildflowers. She kissed my cheek and took my arm.

"This is Bertrand Arnold," she said. "He's one of Dimitri's classmates."

Arnold, who was as many years older than Dimitri as he was younger than I, stood up and put out a hand.

"It's an honor to meet you, Mr. McGill. D has told me a lot about you."

"You're kidding, right?" I said.

"No."

"How the hell's a kid who never says more than three words to me at a time gonna be singing my praises to somebody else?"

The look on the brown man's face was one of bewilderment. He had no prepackaged answer. That told me something.

"I… uh…" he said.

"Leonid," Katrina said in her maternal voice. "You're going to scare the young man."

"What did D tell you?" I asked Bertrand. "About me, I mean."

"He ssssaid that you were a detective. That, that, that he once saw you knock down two men at the beach."

CONEY ISLAND, FIFTEEN YEARS before. Two redneck Brooklynites got it in their heads that a beautiful young white woman like Katrina could find somebody better than a fat little black man. All three kids were with us. Dimitri, the oldest, was not yet eight.

The two guys had a brief span of time in which to retreat. I stood up, walked over to them, and time was up.

"HE REMEMBERED THAT, HUH?" I said.

"Yes," Bertrand replied, vehemently.

"Let's sit down, Leonid," Katrina, the peacemaker, said.

"You look kinda old to be one of D's classmates," I suggested to Bertrand as we sat down.

"My parents own a bakery. Arnold Bakery in Astoria. I wanted to open up a branch store in SoHo. But when the bank asked me for a business plan I realized that I didn't know enough to start a business on my own. So I decided to go back to school. At first it was just an extension course at CCNY. But then I began to realize that I really liked business and so I decided to get a degree. I met Dimitri last year."

It all sounded very plausible. Generation X and their heirs took longer to mature than their elders. I knew nothing about Dimitri's life, but he must have had friends and schoolmates.

"Is D in his room changing or something?" I asked.

"No," Katrina said. "He still hasn't come home."

"Then why are you here?" I asked the boy-faced man.

"I haven't seen Dimitri for a few days," he replied. "He's not in class. He doesn't answer his phone. So I decided to drop by to see if he was okay."

My breathing was normal again. The rage I'd felt at my own helplessness was lessened by the trial of the stairs.

But the headache was getting worse.

"I was asking Mr. Arnold if he knew anybody I could call to get in touch with Dimitri," Katrina said.

"Do you know a friend of D's," I asked Bertrand, "a girl named Tanya-something like that. She might be Russian."

"I've seen him with a blond girl once or twice over the last couple of weeks. I don't know her name. She never spoke and Dimitri would always hustle her off if I was around. I think he was a little jealous."

"Why? You makin' eyes at her?"

"She's very pretty, but I wouldn't go after a girl that he was with."

"I'm very worried, Leonid," Katrina said.

"I talked to Dimitri on the walk back home," I said. It wasn't completely a lie. I had talked to him. "He said that he and Twill were with these Russian girls. Mardi told me that Dimitri's friend was maybe called Tanya."

"Mardi Bitterman?" Katrina said.

"Yeah. She's my secretary now. Twill wanted me to hire her and I think she might work out."

"Do you really want a girl like that working for you?"

"A girl like what?"

"You know what… her history. You were the one who told me."

"She gets raped so now that means she can't work?"

Katrina's stony silence was a throwback to the days when we openly detested each other.

"I should be going," the baker said.

He stood up.

"Could you write down your phone number?" I said. "I mean, if D doesn't show up I might want to ask for your help."

"Sure," the helpful baker replied.

"I'll get pencil and paper," Katrina said.

She didn't want a confrontation with me; not over Mardi Bitterman, at any rate.

Bertrand stood there uncomfortably while I studied him. He could see that I didn't trust a stranger in my home. And he was right. I didn't know what trouble Dimitri was in. Maybe Bert was trying to get the lowdown on my son.

No words had passed between us while Katrina was gone. She returned with a Bic and a wire-ringed notepad.

"This was all I could find," she apologized.

Bert took the notepad and started scribbling.

"The first number is my cell phone," he said. "The second is the bakery, and I put down my e-mail address, too."

"You got a home phone?" I asked.

"No. Just the cell."

He shook my hand and my wife's hand. Katrina walked him to the door.

I remained in my seat, wondering if we lived on the eighteenth floor would I be retired by now.