Lucy turned down the volume of the YouTube video, Mick Fleetwood’s drum solo for “World Turning,” live in concert in 1987.

“Can you hear me now?” she said over the phone to her Aunt Kay. “The signal’s pretty bad here, and the weather isn’t helping.”

“Much better. How are we doing?” Scarpetta’s voice in Lucy’s jawbone.

“I’ve found nothing so far. Which is weird.”

Lucy had three MacBooks going, each screen split into quadrants, displaying Aviation Weather Center updates, data streams from neural network searches, links prompting her that they might lead to websites of interest, Hannah Starr’s e-mail, Lucy’s e-mail, and security camera footage of the actor Hap Judd wearing scrubs in the Park General Hospital morgue before he was famous.

“You sure of the name?” she asked as she scanned the screens, her mind jumping from one preoccupation to the next.

“All I know is what’s stamped on the steel back of it.” Scarpetta’s voice, serious and in a hurry. “BioGraph.” She spelled it again. “And a serial number. Maybe it’s not going to be picked up by the usual software that searches the Internet. Like viruses. If you don’t already know what you’re looking for, you won’t find it.”

“It’s not like antivirus software. The search engines I use aren’t software-driven. I do open-source searches. I’m not finding BioGraph because it’s not on the Net. Nothing published about it. Not on message boards or in blogs or in databases, not in anything.”

“Please don’t hack,” Scarpetta said.

“I simply exploit weaknesses in operating systems.”

“Yes, and if a back door is unlocked and you walk into somebody’s house, it’s not trespassing.”

“No mention of BioGraph or I’d find it.” Lucy wasn’t going to get into their usual debate about the end justifying the means.