"What I don't understand," he said, "is why they always leave the second-floor bathroom window unlocked." His speech was staccato-pressured speech, we call it in psychiatry. "They don't even lock it when we leave the island for Manhattan -which, I guess, is also an island, but I forget that, sometimes. I mean, it's like they figure no burglar will notice the window because it has frosted glass, which is just… stupid. Unless they think nobody would notice it behind the oak tree, which actually makes everything easier, if you can climb. 'Cause no one can see you once you're into the branches. Not that Darwin 's Range Rover robots are exactly Secret Service." He laughed, but it was a quick, anxious laugh that made me think he was high or very scared or manic. "Anyhow, that takes care of my immediate cash crunch. I won't need to bother you." He laughed again. A couple seconds passed. "I think you believed me at the hospital. That's why I'm calling. I want you to know I believe what you said, too. I don't think I really ever wanted to hurt anything or anyone other than my father." He hung up.

I started to pace. I ran my hand over my shaved scalp again and again, a nervous habit that only manifests itself when I sense things have gone very wrong. Billy was on the island-or had been. And, unless he was bluffing, he had managed to slip into the Bishop house and steal something of value. I thought back to our discussion at Payne Whitney, when I had pressed Billy on a potential motive for killing Brooke. And that made a crown of shivers ring my scalp. Because Billy was right: I had argued that his violence had always been about taking things away from his father. I prayed that this time it had been a watch or a ring or a lockbox stuffed with cash, and not little Tess.

I showered and pulled on a fresh pair of jeans. Then I called North Anderson at home. It was only five-twenty, but I had to let him know that Billy was close by-or had been, and that he had apparently invaded the Bishop home.

Tina answered the phone after half a dozen rings. "Hello?" Her voice still had sleep in it.

"Tina, I'm sorry to wake you. It's Frank Clevenger."

She skipped the pleasantries. "Hasn't North called you?" she said.

"No." I picked my cell phone off the bureau and saw that it was registering "Out of Range." "Was he looking for me?" I glanced at the ceiling, cursing the layer of steel or concrete blocking my signal.

"He left for the emergency room about an hour ago. There's something wrong with Tess Bishop."

I felt lightheaded. "Something wrong? Did he say anything else?"

"She stopped breathing," Tina said.

"Where's the hospital?" I asked.

"On South Prospect Street, at Vesper Lane," she said. " Nantucket Cottage Hospital. It's only about a mile out of town. There are little blue hospital signs all over that will point you the right way. You can't miss it."

"Thanks, Tina," I said.

"Sorry to give you bad news, Frank. I'd love to see you. Maybe when this whole thing settles down."

"You will," I said.

I ran down the stairs to the lobby. The woman at the front desk gave me directions to the hospital, but as I raced from street to street in the darkness, I realized I actually could have connected the little, fluorescent "H's" and gotten there just fine. Another thing about Nantucket: Nothing is random. Everything has signage. Over the course of four hundred years, Nantucketers have slowly worn away all the island's rough edges, and all possibility for surprise, so that the island now has its metaphor in every piece of beautiful, smooth, dead driftwood that washes up on its shores.

In such places, I reminded myself, things must happen to let people know they are alive and human. Love affairs take root-complicated ones, full of jealousy, pain, and revenge. Deep depression strikes. Addictions flourish. And, occasionally, some very ugly variety of psychopathology, which has had time to twist on itself grotesquely-like a gnarled, forbidding tree-begins to bear poisonous fruit.

North Anderson 's cruiser was parked near the emergency room, next to an ambulance and two black Range Rovers. I parked alongside them and hurried through the sliding glass doors.

Darwin Bishop, in khakis, a pink polo shirt, and black Gucci loafers, was pacing the lobby, talking on his cell phone. Two of his security guards stood nearby. He turned away and, keeping his voice just above a whisper, said, "Sell all of it at fifty-eight."

I walked up to the receptionist, a blue-haired woman who was obviously beside herself. "I'm Dr. Clevenger," I said. "I'm here to see Captain Anderson."

"He's in Room Five, with Mrs. Bishop and the baby," she said, wringing her thickly veined hands. "I hope you can do something. She's so tiny."

"You're not going in there," Bishop said, from behind me.

I turned around. He was standing with his two goons. "What happened to Tess?" I asked flatly.

He ignored the question. "You're not welcome here," he said.

I started past the receptionist. But I hadn't taken more than four steps when someone grabbed my wrist and jerked it, hard, behind my back, his arm falling across my neck.

I looked over my straining shoulder and saw one of the bodyguards had hold of me. It was an amateur move that made me question whether Bishop had hired him away from a Kmart. I leaned slightly forward, then drove my free elbow into the man's rib cage. A sharp crack told me I had hit home. He groaned and let go. Then his friend started coming at me.

"That's the end of it!" Anderson yelled from the hallway, half a dozen yards past the reception desk. He walked toward us.

Bishop pointed at me, but kept his distance. "I want him out of here."

Anderson walked up to me. "Let's go outside. I can bring you up to speed."

I took a mental note of that minor surrender and followed him back through the sliding glass doors, over to his cruiser.

"What the hell is going on?" I said. "What happened to Tess?"

He leaned against the hood. "Cardiac arrest," he said. "They got her back, but her heart's still not beating the right way. They're not sure if there's damage to her brain from lack of oxygen."

"My God."

"The Bishops rushed her to the ER at about three a.m." he explained. "I guess she'd been crying for about an hour before she stopped breathing. Julia and Claire were with her the whole time. When she passed out, they called 911. Actually, they had Darwin place the call."

"What does the doctor say?"

"She drew a toxic screen and found a high level of nor… trip… something."

"Nortriptyline," I said.

"That's it."

Nortriptyline is an antidepressant medication that can be fatal in overdose. Too high a concentration in the bloodstream slows electrical conduction through cardiac muscle, making the heart skip beats, then spiral into chaotic rhythms that pump no blood. "Where did the nortriptyline come from?" I asked.

"It's Julia's, prescribed by a psychiatrist in Aspen," Anderson said. "She was skiing there with Darwin a year or so back and was really feeling low. She says she felt better when they got home, so she stopped using it."

"But she kept the bottle?" I said.

"Right."

"So what are you thinking?"

"Actually, Frank," Anderson said, "it's looking like Billy's our man."

I hadn't even broached the news about Billy having broken into the Bishops' home. "Why do you say that?"

"He snuck into the house through a bathroom window during Brooke's funeral, stole some cash and jewelry. I guess he must have decided to take a little side trip to the nursery and feed Tess the pills. Claire had been writing letters in Darwin 's study most of the night."

"How did you know he'd been in the house at all?" I asked.

"He left a note," Anderson said.

"What did it say?"

"Payback's a bitch. Love, Billy."