DR. KAY SCARPETTA moves the tiny glass vial close to candlelight, illuminating a maggot drifting in a poisonous bath of ethanol.

At a glance, she knows the exact stage of metamorphosis before the creamy carcass, no larger than a grain of rice, was preserved in a specimen vessel fitted with a black screw cap. Had the larva lived, it would have matured into a bluebottle Calliphora vicina, a blow fly. It might have laid its eggs in a dead human body's mouth or eyes, or in a living person's malodorous wounds.

"Thank you very much," Scarpetta says, looking around the table at the fourteen cops and crime-scene technicians of the National Forensic Academy's class of 2003. Her eyes linger on Nic Robillard's innocent face. "I don't know who collected this from a location best not to contemplate at the dinner table, and preserved it with me in mind… but…"

Blank looks and shrugs.

"I have to say that this is the first time I've been given a maggot as a gift."

No one claims responsibility, but if there is a fact Scarpetta has never doubted, it is a cop's ability to bluff and, when necessary, outright lie. Having noticed a tug at the corner of Nic Robillard's mouth before anyone else realized that a maggot had joined them at the dinner table, Scarpetta has a suspect in mind.

The light of the flame moves over the vial in Scarpetta's fingertips, her nails neatly filed short and square, her hand steady and elegant but strong from years of manipulating the unwilling dead and cutting through their stubborn tissue and bone.

Unfortunately for Nic, her classmates aren't laughing, and humiliation finds her like a frigid draft. After ten weeks with cops she should now count as comrades and friends, she is still Nic the Hick from Zachary, Louisiana, a town of twelve thousand, where, until recently, murder was an almost unheard-of atrocity. It was not unusual for Zachary to go for years without one.

Most of Nic's classmates are so jaded by working homicides that they have come up with their own categories for them: real murders, misdemeanor murders, even urban renewal. Nic doesn't have her own pet categories. Murder is murder. So far in her eight-year career, she has worked only two, both of them domestic shootings. It was awful the first day of class when an instructor went from one cop to another, asking how many homicides each of their departments averaged a year. None, Nic said. Then he asked the size of each cop's department. Thirty-five, Nic said. Or smaller than my eighth-grade class, as one of her new classmates put it. From the beginning of what was supposed to be the greatest opportunity of her life, Nic quit trying to fit in, accepting that in the police way of defining the universe, she was a them, not an us.

Her rather whimsical maggot mischief, she realizes with regret, was a breach of something (she's not sure what), but without a doubt she should never have decided to give a gift, serious or otherwise, to the legendary forensic pathologist Dr. Kay Scarpetta. Nic's face heats up, and a cold sweat dampens her armpits as she watches for her hero's reaction, unable to read it, probably because Nic is stunned stupid by insecurity and embarrassment.

"So I'll call her Maggie, although we really can't determine gender yet," Scarpetta decides, her wire-rim glasses reflecting shifting candlelight. "But a good enough name for a maggot, I think." A ceiling fan snaps and whips the candle flame inside its glass globe as she holds up the vial. "Who's going to tell me which instar Maggie is? What life stage was she in before someone"-she scans the faces at the table, pausing on Nic's again-"dropped her in this little bottle of ethanol? And by the way, I suspect Maggie aspirated and drowned. Maggots need air the same way we do."

"What asshole drowned a maggot?" one of the cops snipes.

"Yeah. Imagine inhaling alcohol…"

"What'cha talking about, Joey? You been inhaling it all night."

A dark, ominous humor begins to rumble like a distant storm, and Nic doesn't know how to duck out of it. She leans back in her chair, crossing her arms at her chest, doing her best to look indifferent as her mind unexpectedly plays one of her fathers worn-out storm warnings: Now, Nic, honey, when there's lightning, don't stand alone or think you'll be protected by hiding in the trees. Find the nearest ditch and lie as low in it as you can. At the moment, she has no place to hide but in her own silence.

"Hey Doc, we already took our last test."

"Who brought homework to our party?"

"Yeah, we're off duty."

"Off duty, I see," Scarpetta muses. "So if you're off duty when the dead body of a missing person has just been found, you're not going to respond. Is that what you're saying?"

"I'd have to wait until my bourbon wears off," says a cop whose shaved head is so shiny it looks waxed.

"That's a thought," she says.

Now the cops are laughing-everyone but Nic.

"It can happen." Scarpetta sets the vial next to her wineglass. "At any given moment, we can get a call. It may prove to be the worst call of our careers, and here we are, slightly buzzed from a few drinks on our time off, or maybe sick, or in the middle of a fight with a lover, a friend, one of the kids."

She pushes away her half-eaten yellowfin tuna and folds her hands on top of the checkered tablecloth.

"But cases can't wait," she adds.

"Seriously. Isn't it true that some can?" asks a Chicago detective his classmates call Popeye because of the anchor tattooed on his left forearm. "Like bones in a well or buried in a basement. Or a body under a slab of concrete. I mean, they ain't going anywhere."

"The dead are impatient," Scarpetta says.

NIGHT ON THE BAYOU reminds Jay Talley of a Cajun band of bullfrogs playing bass, and peepers screaming on electric guitars, and cicadas and crickets rasping washboards and sawing fiddles.

He shines a flashlight near the dark, arthritic shape of an old cypress tree, and alligator eyes flash and vanish beneath black water. The light simmers with the ominous soft sound of mosquitoes as the BayStealth drifts, the outboard motor cut. Jay sits in the captain's chair and idly surveys the woman in the fish box not far below his feet. When he was boat shopping several years ago, this particular BayStealth excited him. The fish box beneath the floor is long and deep enough to hold more than a hundred and twenty pounds of ice and fish, or a woman built the way he likes.

Her wide, panicked eyes shine in the dark. In daylight, they are blue, a deep, beautiful blue. She painfully screws them shut as Jay caresses her with the beam of the flashlight, starting with her mature, pretty face, all the way down to her red painted toenails. She is blonde, probably in her early- to mid-forties, but looks younger than that, petite but curvaceous. The fiberglass fish box is lined with orange boat cushions, dirty and stained black from old blood. Jay was thoughtful, even sweet when he bound her wrists and ankles loosely so the yellow nylon rope wouldn't cut off her circulation. He told her that the rope wouldn't abrade her soft flesh as long as she didn't struggle.