ONE WEST 72nd Street turned out to be the Dakota, the famous Gothic castle-like building where John Len-non had lived before he was shot in front of it. It was also the place where the lady who gives birth to the devil in Rosemary’s Baby lived, I remembered cheerfully. The good omens just kept on coming this afternoon.

I passed the building and left my van up around the next corner on Columbus and walked back along 72nd. If in the unlikely case this was a kidnapping, it already could be under surveillance. I definitely did not want to advertise that the family had contacted the police.

I passed through a wrought-iron gate at the Dakota’s entrance. Its double-wide arched entryway was the very spot where Chapman had killed the ex-Beatle, shooting him in the back before he could get into the lobby entrance up a short set of stairs to the right. The building was a popular sightseeing tour stop. Yoko, who still lived here, had to be overjoyed when she saw people looking around for bullet holes.

The heavy brass barred door opened as I reached the top. A portly Asian doorman in a hunter green suit coat and hat stood beside an ALL VISITORS MUST BE ANNOUNCED sign.

“I’m here to see the Dunnings,” I said, discreetly showing him my shield.

After I was announced, an elderly hall man appeared and guided me through the lobby. The walls had the richest, darkest mahogany paneling I’d ever seen. A massive ballroom chandelier and brass wall sconces softly lit the intricately detailed ceiling moldings and white travertine marble floor.

The hall man, in turn, passed me off to an elevator man. Upstairs, a diminutive butler waved me in through the open door of 10 B.

Through the nearly double-height French doors, I could see the whole way through the Dunnings’ apartment to Central Park. The grand rooms were arrayed in the classic enfilade design, allowing more than one way into each room so guests could avoid the servants. The wood floors, like the paneled walls, were Cuban mahogany. They were laid out in a herringbone pattern with what looked like a black-walnut trim.

A striking black-haired woman came quickly down the long corridor of the apartment. She was wearing a rumpled blue evening dress, and even from a distance, the agony in her fine-boned face was unmistakable. My annoyance at being called in dissipated as my heart went out to her. Even with her elegant clothes and her surroundings, she was just a concerned mom sick with worry.

“Thank God you’ve come. Detective Bennett, is it?” she said with an English accent. “It’s my son, Jacob. Something’s happened to him.”

“I’m here to help you find him, ma’am,” I said as reassuringly as I could while I took out my notebook. “When was the last time you saw or spoke to Jacob?”

“I spoke to him three days ago. Jacob lives at school. At NYU. Hayden Hall, right alongside Washington Square Park. My husband is still down there with my father. They’ve spoken to his friends, and no one has seen him since Friday. Not his roommate. No one.”

Maybe he met a cute girl, I felt like saying to her.

“Not seeing someone for a few days might not necessarily mean something’s wrong, Mrs. Dunning. Is there a specific reason why you think something’s happened to him?”

“My husband and I had our twenty-fifth wedding anniversary last night at Le Cirque. We’d planned it with Jacob for months. Jacob’s grandfather flew in from Bordeaux for the occasion. Jacob would not have missed it. He is our only child. You don’t understand how close we are. He would not have missed our special event or the rare chance to see his grandfather.”

I was starting to understand her concern. What she was telling me did seem strange.

“Did he say anything to you when you last spoke to him? Anything odd? Someone new he might have met or—”

That’s when the phone on the antique sideboard beside her rang. She stared in horror at the caller ID number, then at me as it rang again.

“I don’t know that number,” she said, raw panic in her voice. “I don’t know that number!”

“That’s okay,” I said, trying to calm her down. I scratched down the number, and let my instincts kick in.

“Listen, April. Look at me. If it’s someone involved with Jacob being gone—I don’t think it is, but if it is—you need to ask them exactly what you need to do in order to get your son back, okay? And if you can, say that you want to speak to Jacob.”

Tears were streaming down her face as the phone rang again. She used a shaking fist to wipe them away before she grabbed the receiver. I listened at an extension in the adjacent study. I pressed the phone’s answering machine’s Record button as I lifted the receiver.

“Yes? This is April Dunning.”

“I have Jacob,” a strangely serene voice said. “Listen.”

There was a click and hum on the line and then what sounded like a recording.

“Question number nine: If you were born in Sudan, what would be your chances of living to forty? And what does that have to do with your cute little red iPod nano?”

“I don’t know,” a young man sobbed. “Stop. Please stop.”

The recording clicked off.

“You’ll receive instructions in exactly three hours,” the calm voice said. “Follow them to the letter or you’ll never see your son alive again. No police. No FBI.”

The connection was cut. I was hanging up the extension when there was a crash in the hallway. Mrs. Dunning was kneeling on the herringbone floor, sobbing inconsolably.

“It’s Jacob,” she moaned. “That bastard has my Jacob.”

The butler arrived a step before me and helped her into a chair.

I speed-dialed the chief. Unbelievable. This really was a kidnapping. We had no time to waste to get set up. We needed to hustle if we were going to have all our teams in place in three hours. It was going to be close.

I frowned out the window. Down across Central Park West, a tour bus was disembarking, people checking their cameras as they crowded toward the Strawberry Fields John Lennon memorial. My boss’s phone rang with a painful slowness as Mrs. Dunning’s cries carried through the high-ceilinged rooms.

“C’mon,” I said in frustration. “Pick up.”