"When did you last talk to Lorna?" I asked.

"Friday morning, April twentieth," he said. "I remember because I had a golf tournament that weekend, and I was hoping to leave work early and get out to the driving range. She was due in at one, but she phoned and said she was suffering a real bad allergy attack. She was trying to get out of town anyway, you know, to find some relief from the pollen count, so I told her to go ahead and take the day off. There wasn't any point having her come in if she was feeling punk. According to the police, she died the next day."

"So she was supposed to be back at work May seventh?"

"I'd have to check the date. It would have been two weeks from Monday, and they'd found her by then." He reverted back to tour guide mode, talking about construction costs as we entered the next section of the plant. The low hum of rushing water and the smell of chlorine created an altered awareness. The general air of the place was of backwash valves and pressurized tanks on the verge of exploding. It looked as though one good jolt from the San Andreas fault and the whole facility would collapse, spewing forth billions of gallons of water and debris, which would kill both of us in seconds. I edged up closer to him, feigning an interest I didn't quite feel.

When I tuned in again, he was saying, "The water is prechlorinated to kill disease-causing organisms. Then we add coagulants, which cause the fine particles to clump together. Polymers are generally added in the coagulation process to improve the formation of insoluble floes that can then be filtered out. We have a lab in the back so we can monitor the water quality."

Oh, great. Now I had to worry about disease-causing organisms on the loose in the lab. Drinking water used to be such a simple matter for me. Get a glass, turn the tap on, fill water to the brim, and gulp it down until you burped. I never thought about insoluble floc or coagulants. Barf.

Simultaneous with his explanation of the plant operation, which he must have done a hundred times in the past, I could see him scrutinize every inch of the place in preparation for the upcoming inspection. We clattered down a short flight of concrete steps and through a door to the outside. The day seemed curiously bright after the artificial light inside, and the damp air was perfumed with chemicals. Long walkways ran between blocks of open basins surrounded by metal railings, where still water sat as calm as glass, reflecting gray sky and the underside of the concrete grids.

"These are the flocculation and coagulation basins. The water's kept circulating to create a floc of good size and density for later removal in the sedimentation basins."

I was saying "Mmm"- and "Uhn-hun" -type things.

He talked on, taking the whole process for granted. What I was looking at (trying not to register my profound distaste) were still troughs where water sat with a viscous-looking liquid on its surface, bubble-coated and inky. The sludge was as black as licorice and looked as if it were made up of melted tires just coming to the boil. Perversely, I pictured a plunge into the tarry depths, wondering if you'd flail to the surface with your flesh in tatters from all the chemicals. Steven Spielberg could have a ball with this stuff.

"You're not with the police department?" he asked. He hadn't stopped walking once.

"I was, once upon a time. Temperamentally, I'm better suited to the private sector."

I was trotting at his heels like a kid on a field trip, irretrievably separated from the rest of the class. Out the backside of the plant, there was a wide, shallow reservoir of cracked black sediment, like a thawing pond of crud. Thousands of years from now, anthropologists would dig this up and imagine it was some kind of sacrificial basin.

He asked, "Are you allowed to say who you're working for? Or is that privileged information?"

"Lorna's parents," I said. "Sometimes I prefer not to give out the information, but in this case it's a straightforward matter. No big secret. I had this same conversation with Serena last night."

"My soon-to-be ex? Well, that's an interesting point of departure. Why her? Because she found the body?"

"That's right. I couldn't get to sleep. I knew she worked the night shift at St. Terry's, so I thought I might as well talk to her first. If I'd thought you were up, I'd have knocked on your door as well."

"Enterprising," he remarked.

"I'm getting paid fifty bucks an hour for this. Makes sense to work every chance I get."

"How's it going so far?"

"Right now, I'm at the information-gathering phase, trying to get a feel for what I'm dealing with. I understand Lorna worked for you for what, three years?"