I called my mother on the way home to ask if we needed anything. She seemed a little thrown; maybe it was the “we.” She recovered fast, though, and assigned me choy sum, peanuts, and soft tofu.

Making tofu’s a cottage industry in Chinatown. Everyone has a favorite back room, basement, or fourth-floor walk-up where someone’s granny stirs vats and scoops the silky stuff into a container you bring along. The place I like is a Baxter Street hole-in-the-wall. If the route there took me right by Bright Hopes, was that my fault? I told myself I wouldn’t go in unless I saw Mr. Chen out on the shop floor.

I didn’t. In fact, the shop was already closed. I turned up Baxter, but I was hit by a nagging sense I’d seen and ignored a familiar face. I don’t like to be rude unless I mean to be, so I looked over my shoulder, scanning the choreography of the street. No, I was wrong.

No, I was right. Not someone I knew. But a familiar round face, with what must be a seriously guilty conscience: As soon as our eyes met, he was off.

“Wong Pan!” I surged past three teenage girls whose linked elbows dammed the sidewalk. “Wait!”

For a fat man, he could move. He cut through traffic and I charged after, jay-running across Canal. “Wong Pan!” Had he found Mr. Chen? Had they spoken, made a deal? Knowing Wong Pan was likely a killer, would Mr. Chen do that?

For his mother’s jewelry? Damn right he would.

“Stop!” I yelled, but of course Wong Pan didn’t stop. No one stopped him for me, either; by the time my shouts registered, people had already sidestepped out of his way. I was gaining on him, though. He slipped down Walker and turned on Lafayette. Just before the courthouse I went into overdrive, did a broad jump, and got hold of his shirt. I spun him around and threw us both off balance. He grabbed me, we did a jig, neither of us fell, and then one of us felt a gun in her ribs.

I stopped moving. “You won’t shoot me here.”

“I shoot you where I have to.” He put an arm around me. His gun lurked under my jacket. “Smile like you glad see me.”

“I am glad to see you. I’ve been looking for you. You killed my friend.” I showed my teeth in imitation of Mulgrew.

“I kill you, too. Stay away. Don’t wanting more trouble.”

“No, you have enough already. This would be the time to turn yourself in.”

He laughed like ice cracking. I was never so lonely for my gun in my life. “Sorry, your friend.” He shoved his moon face close to my ear. “All I want is get my money, go away. You leave me alone, no one else get hurt, too. You don’t, remember this: For me, nothing to lose.”

A sudden hard push and I was face-to-face with a brick wall. By the time I spun around, Wong Pan was gone.

I don’t know if it was true about the karma points for eating dinner with my mother, but I hoped so, because I needed them. Mary, hearing what had happened, hit the roof.

“You let him get away?”

“He pulled a gun and mashed me into a wall!”

“So? You were okay with chasing him down the street without calling us, why not try for the collar, too?”

“I didn’t have time to call you!” Stop, Lydia. Breathe. “You’re right. I’m sorry. But Mary, anyway, now we know for sure he’s here. And that he killed Joel.”

“That’s supposed to make me feel better, a known killer on the loose?”

“And we know he knows about Mr. Chen.”

“No, we don’t.”

“What else was he doing down here?”

“What you thought originally he’d be doing. Trying to sell his jewelry.”

“Rosalie’s jewelry.”

“What?”

“Nothing. But what if he does know about Mr. Chen? Or finds out? They could have a secret deal.”

“You’re asking me to put a surveillance on Chen?”

“I wouldn’t ask you for the time of day.”

“You wouldn’t get it, either. But it’s not a bad idea. Even if it was yours. You think you can stay out of trouble until morning?”

She hung up without my answer. I think she was afraid of what I’d say.

On the way to actually pick up the tofu, I called Bill and filled him in. Unlike Mary, he was neither surprised nor annoyed that I’d chased an armed suspect down the street.

“It’s unlike you to lose him, though.”

“It’s the jet lag. Do you think I should warn Mr. Chen? Tell him not to do business with him and call if he turns up?”

“Of course.”

“Do you think it’ll do any good?”

“No.”

It especially wouldn’t do any good if Mr. Chen didn’t pick up his voice mail, because that was as close to him as I got.

Dinner, though delayed, was delicious. I didn’t tell my mother about Wong Pan. We talked about some cousins in the Philippines she’d just heard from, and others in Sidney who never write. I mentioned seeing Clifford Kwan, at which my mother heaved a major sigh about the grief Clifford caused his mother by being willful and selfish. Sensing landmines, I steered the conversation elsewhere: the progress of the melons in Ted’s backyard. After dinner she cleared the table while I did the dishes, with minimal instruction from her on which was the dish sponge as opposed to the counter sponge, and how hot the water had to be.

The sky’s vibrant blue had softened to lilac and I’d just dropped the sheaf of diary Xeroxes on my desk when the Bonanza song rang out. “I’m going to have to give you a new ringtone,” I told Bill. “That one’s getting on my nerves.”

“If I apologize, will you meet me uptown?”

“I won’t accept that apology because you had nothing to do with the ringtone. Does that mean I can stay home?”

Apparently it didn’t. “Half an hour. At Columbia. To see a friend of a friend.”

Once, you had to pass a gate to get onto the Columbia campus, a placid academic island amid Manhattan’s surf and riptides. Now university buildings line Broadway and the side streets, too. But the gate still stands, opening ornamentally, if unnecessarily, to the old quad. I met Bill there.

“It took a lot of blind faith to get me out again tonight,” I informed him.

“I appreciate that. Dr. Edwards called me right before I called you. He’s a busy guy, but he has time tonight after his evening class. You okay?”

“Why wouldn’t I be?”

“Something about your face meeting a brick wall.”

“I’m fine. Just a little furious. This Dr. Edwards is who?”

“Remember I said I was calling a friend? One of the handball regulars is a Columbia prof.”

“This is him?”

“A friend of his. The go-to guy on modern Chinese history.”

A lamplit brick walk, a security guard, and an elevator later, Bill and I poked our heads into a book-lined office. Book-paved, and pretty much book-furnished, too, except for the computer on the desk and the Manchu ancestor painting on the wall. Though if the rangy sixtyish man whose cowboy boots rested on the desk was Bill’s friend’s friend, they weren’t his ancestors. Unless black Africans had come farther along the Silk Road than I knew. Admittedly, they weren’t my ancestors either: The eyes and hair were the same, but the pale skins and formal silks marked these people as aristocrats, from a time when my ocher-faced forebears would have been lucky to find burlap to tuck around themselves while they worked the fields.

At the rap of Bill’s knuckles the man lifted his eyes from a lapfull of papers. “Hey! You Smith? This your partner?” He swung his boots off the desk and shook hands with us both. “William Edwards.” He bustled around, shifting books to the floor. “Go on, sit. They’ll behave.”

“The books?” Bill asked.

“They like chairs better, but they’re adaptable. So you’re a friend of Larry’s?”

“Handball.”

“Is he as cutthroat there as here?”

“He kills me.”

“And then stands over your corpse and cackles, right? So. Larry the molecular biologist tells me you’re interested in a minor CCP official from the early years of the People’s Republic. Like he knows what that means. He doesn’t know what any sentence means that doesn’t include the words ‘electron microscope.’ ”