IT WAS another shot in the dark, but I jumped in the sedan and floored it to the airport. Traffic was heavy, then light, then heavy again. I parked at the Departures curb, left the siren spinning on the dash, bolted inside, and scanned the boards. Flight 201 for Mexico City, gate 16. Scheduled to take off in just under an hour.

My badge got me through customs without any hassle. I took the escalator two steps at a time, shouldered my way past men and women of all ages. When I got to the gate, the seating area was already packed. I stood back and searched.

Families, businesspeople, what looked to be a high school marching band traveling in uniform. The women were all too old or young, tall or short, thin or fat.

I checked the adjacent gates, the nearby restaurants, bars, shops. No sign of Serena anywhere. I walked back to gate 16, dropped onto a bench with my head in my hands, and wondered if there was any way I might board the flight myself. I felt like a gambler who’d bet his home and lost. Now it was just a question of who’d come to collect the debt: Vincent or Heidi.

And then, when I looked up, there she was—exiting the ladies’ room directly across from where I was sitting. She was wearing a straw sun hat with an enormous brim and a plaid scarf that she’d pulled up over her mouth, but it was her. Same slim build, same jet-black hair. And she was carrying a small, tan duffel bag. I hunched forward, dropped my head back into my hands, waited for her to pass.

I counted to ten, then dared a look over my shoulder. She was sitting by the window, gazing out at the runway traffic, looking as though she didn’t know what to do with herself, as though she might never know what to do with herself again. I’d have felt sorry for her if it weren’t for the fact that I had my own future to protect. Mine, and Sarah’s, too.

And then it occurred to me: Now what?

Things would go much better for me if I wasn’t the one to take her downtown. Vincent wouldn’t like that one bit, and neither would Heidi. This wasn’t my case. She didn’t want me anywhere near it, and the fact that I kept pushing would only ratchet up her suspicions, make her turn over rocks I couldn’t have disturbed.

I squinted at the gate’s monitor. Forty minutes until boarding. I got up, walked as far away as I could without losing sight of that tentlike hat, and took out both phones: business and burner. Heidi and Vincent. Good and evil, at least in the eyes of the law. I balanced one phone in each palm, thinking maybe I’d just go with the heavier of the two.

The cop phone won out. I called Randy. I figured I’d throw him another career booster. He picked up on the first ring, didn’t let me get out more than a hello before he started jabbering.

“Looks like Marty’s confession is legit,” he said. “Like, 100 percent legit. We’re talking slam dunk. I—”

“That’s great, Randy—”

“Randolph.”

“Sorry. I’m glad you’re batting a thousand, but I need you to listen—this is important.”

“Okay.”

“Tell Heidi that Serena Flores, housemaid to Anthony Costello, is sitting at gate 16 in the Tampa airport, waiting to board a flight to Mexico City.”

“Right now?”

“Right now. But listen, this can’t come from me.”

“So who’s it supposed to come from?”

“Tell her you put out feelers. One of your informants got back to you. Trust me, this is bigger than a homeless guy’s murder. You’ll probably get a commendation.”

“And you’re just handing it to me?”

I could see his eyes turning into little sergeant’s badges.

“I’m the gift that keeps on giving. Now go!”

And it was true: I had more gifts to give him. Or at least one more gift: a very large veterinarian named Símon Flores. I’d keep feeding Randy tips. He’d be my conduit to Heidi. The next tip would have something to do with Anthony Costello’s files on Serena and several other choice items turning up in Símon’s apartment. Of course, Símon would be gone and buried by then. Vincent would see to that.

I hung up, headed into one of those airport junk stores, and bought the tackiest outfit I could sling together: a Hawaiian sweatshirt, a HAIL TO THE GATORS baseball cap, mirrored sunglasses. Then I went into the bathroom and changed. When I was done, I stood for a beat checking myself out in the mirror. I certainly didn’t look like Detective Sean Walsh. Not at first, second, or third glance. I was all set to sit back and watch the show, no matter who came for Serena.

By then, I figured I’d given Heidi a big enough head start. I walked back to gate 16, pulled out the burner phone, and dialed Vincent’s number.

“I’m assuming you know better than to call without good news,” he said. “So, do you have her?”

“Not exactly. I got a tip.”

I told him where she was. I told him how long he had to come get her.

“I thought I was clear: that’s your job, Detective.”

“But here’s the thing: I’m at a murder scene on the ass end of town. I couldn’t get there in time if I wanted to.”

“How reliable is this tip?”

“One hundred percent.”

I hung up. I figured this way I’d at least have an argument to sell. I told you, Vincent. I went straight to you, as soon as I heard. It’s not my fault my boss got the same tip. Besides, I’d say, I have something better than Serena: I have Anthony’s killer.

With the hour of departure approaching, flight 201 looked to be packed. Not a spare seat anywhere in the waiting area, and plenty of people siting on the floor. I leaned against a support beam and watched. Serena had pulled her hat over her face as though she was napping. Trumpet-playing members of the marching band decided this would be a good time and place to tune their instruments, at least until their chaperone told them to cut it out. Between the band and a half dozen newborns, it was going to be a very unpleasant flight for a whole lot of passengers.

Countdown to boarding hit the fifteen-minute mark. I couldn’t stop myself from casting glances in every direction. If no one showed, I’d have no choice but to bring her in myself. Heidi would come down on me hard, and Vincent would have his boys give me a world-record tune-up before outing me to the press. But once Serena set foot on that plane, there’d be nobody to say Sarah didn’t do it.

A flight attendant cleared his throat into the sound system, announced that the plane was ready to begin boarding. I stutter-stepped forward, then pulled up short. Two airport rent-a-cops had entered the seating area. They were walking the rows, comparing each female face to an eight-by-ten photo. Serena spotted them. Even from a dozen yards away I could see the blind fear take hold. She broke into a full-out run, but it didn’t do any good: the taller of the two men was on top of her before she cleared the waiting area. I watched them cuff her, lead her away.

At first I figured Heidi had sent them. It wasn’t her style, but maybe she got caught in bumper-to-bumper traffic, called ahead. Then I realized: they were Vincent’s men. They had to be. Airport cops on the up-and-up wouldn’t have left Serena’s bag behind.