“For how long?”

“Until hell freezes over,” Monk said. “And we’ll know when that happens because she’ll be covered in ice.”

It was getting dark when we swapped cars with Julie outside of Monk’s apartment. She couldn’t wait to pick up her friends and put some miles on the Lexus cruising around San Francisco, which was just fine with Monk and less fine with me.

I didn’t think she’d be in any danger from Nick Slade. I was more concerned about the trouble that she and her friends might get into on their own.

As soon as Julie left, Danielle pulled up behind us in her Mini Cooper convertible and we met on the sidewalk for a quick briefing.

I didn’t want to tell her the whole story yet, and Monk agreed with me, so we left out the part about Nick Slade being a triple murderer.

All she needed to know was that we were keeping an eye on Linda Wurzel.

Danielle probably suspected that there was more going on than we were letting on, but she didn’t press the point. She pulled out a map of Sea Cliff, an exclusive, very wealthy neighborhood that was tucked between the Presidio and Lincoln Park and boasted breathtaking views of the Pacific, the Golden Gate Bridge, the Marin headlands, and, on clear days, Mount Tamalpais.

Linda Wurzel lived on a curving street. If we parked a car at either end, we could keep her house in sight and follow her no matter which direction she took when she left.

By keeping in touch via cell phone, we could then tail her wherever she went, switching off who was behind her so she wouldn’t notice that she was being followed.

That was how the professionals did it and, for the first time, I actually felt like one.

“What are we following her for?” Danielle said.

“We’ll know when we see it,” Monk said.

He ran into his apartment to get Wheat Thins, water, and extra wipes and then we sped off to Wurzel’s estate.

Two stone pillars on the western and eastern corners of Twenty-fifth Avenue and El Camino Del Mar marked the entrance to Sea Cliff so that everyone knew that this was a neighborhood set apart from the rest of the city.

Nobody needed a couple of pillars to know that. The smell of money was enough.

The immaculately maintained Mediterranean mansions of Sea Cliff were surrounded by gardens of sculpted shrubs and beautiful pines set against sweeping bay views.

We parked on the west end of the street, Danielle took the east.

I rolled down the window a crack so I could enjoy the brisk sea breeze and hear the waves crashing against the cliffs below.

Wurzel’s house was huge and stately, surrounded by a tall wrought-iron fence with security cameras discreetly placed in key positions along the perimeter. The bushes on the property were pruned to look like swirling tornadoes of green and her trees were shaped like enormous balls. A polished cobblestone driveway curved past the front door on its way to the garage to the western side, presumably so a chauffeur could drop Wurzel off before parking the car.

We timed things just right. A few moments after we parked, Wurzel passed us in a two-toned, silver-and-gray Maybach that made an S-class Mercedes look like a Toyota Corolla.

The gates of her mansion swung open and she drove into her compound, parked at her front steps, and hustled into the house.

She’d driven herself to and from Chinatown. What was the point of having such a huge car if you weren’t going to enjoy the luxury of riding in the reclining, heated, double-quilted, nubuck leather backseat, the Wall Street Journal spread out on your gold-trimmed cherrywood desk while CNN played on one of the four flat-screen TVs?

That was why I didn’t get the same setup in my Buick.

For the first four hours that we sat there, I passed the time trying to think of ways that we could prove that Nick Slade was guilty of murdering Peschel or Braddock.

I came up with a few ways but then I shot them down myself without even telling Monk about them.

My first thought was that maybe someone had seen his Bentley parked in Peschel’s neighborhood the morning of the murder.

But even if we could establish that the Bentley was his, that wouldn’t prove he had killed Peschel, only that he had visited with him, which he’d done a few times before.

And what if Slade hadn’t taken his distinctive Bentley to Peschel’s but chose to be discreet by using one of the cars from his fleet instead? Wouldn’t his tracking system have a record of where he went?

Then again, the record wouldn’t prove he was in the car, or that he’d killed Peschel. And that was assuming Slade hadn’t erased the record so the car’s travel history couldn’t be dug up.

I was getting nowhere proving that Slade killed Peschel, so I shifted my thinking to the Braddock case.

Obviously Slade was the guy in the elevator in the beefeater suit. If there was footage of Stottlemeyer entering and leaving the hotel, wouldn’t there be tape of Slade, too?

Then again, so what if there was?

Even if he was there at the time of the murder, that wouldn’t prove he’d killed Braddock, only that he was in the hotel. And he could claim he was there for a number of legitimate reasons-to have a drink, to visit friends, or to check up on his operatives, who were, after all, responsible for security at the Dorchester.

And since Intertect controlled the surveillance system, Slade probably had the ability to erase himself from the video if he wanted to.

Monk was right: Stottlemeyer was screwed. And I wasn’t sure what sitting on Linda Wurzel would do to change that. But maybe I was just tired and grumpy. I also regretted not using the bathroom while we were at Monk’s apartment.

I called Danielle to check in on her. She was listening to an unabridged audiobook of Anna Karenina, sipping green tea, eating trail mix, and generally having a grand time on her first stakeout.

I had the Murder, She Wrote book in my purse, but I couldn’t read it because turning on the interior light would alert Wurzel and her neighbors that we were sitting out there. There had already been a couple of private security patrols but we’d ducked down each time they’d passed.

So I napped.

It seemed like I’d closed my eyes for only a second when Monk nudged me awake. It was after midnight and Wurzel was leaving her house in the Maybach and heading in Danielle’s direction.

I gave her a call, alerted her that Wurzel was coming, and started the car.

I have to admit it was exciting. I’d never tailed anyone like this before. And Danielle sounded thrilled, too. We stayed in constant contact by phone so that we could take turns driving behind or in front of Wurzel.

She led us east across the city to Mission Bay and the long-abandoned, decaying Bethlehem Steel warehouses, foundries, and machine shops on the piers.

It wasn’t exactly a cheery place.

The huge buildings were decomposing like corpses, the weathered brick chipping away, the windows shattered, the corrugating metal peeling off in rusted, rotting strips.

If you’ve ever watched a cop show, then you know only bad things happen when you visit abandoned warehouses at night.

The last time I’d been here it was to see the body of a murdered cop who’d made the mistake of meeting the wrong person in the darkness of this decaying industrial wasteland.

Once it was clear where Wurzel was going, we hung a few blocks back, our headlights turned off, watching as her car disappeared into one of the hangar-sized buildings.

I turned to Monk. “Now what?”

“We follow her,” Monk said.

I didn’t like that idea much at all. “Shouldn’t we call the police?”