Seeing Garret's bookshelf the night before, stocked with titles by the poet Yeats, had clued me in to his guilt. Julia had quoted Yeats in the mystery letter:

My temptation is quiet.

Here at life's end.

I had finally realized that Julia had intended that letter for Garret, not her therapist or some business associate of Darwin 's. She had taken Garret as her lover.

Garret had been the one who had attacked me in a jealous rage outside Mass General Hospital, uttering a line from Yeats before plunging a knife into my back:

What could she have done, being what she is?

"Good morning," Garret said softly.

I looked up at him. The muscles of his chest twitched. He was closing and opening his fists rhythmically. Wired. "Don't do this," I said.

"You need her so badly," he said. "Take her."

"Let me help you," I said.

He laughed a gruesome laugh, craning his neck toward the dark sky, like some sort of deranged animal. Then he looked down at me, his eyes wide. "You wanted this," he said. "You made this happen."

A wave of nausea swept over me. Was it possible my psychological strategy-increasing the sexual tension in the house to a fever pitch-had actually been an unconscious way of finishing off my last rival for Julia's attentions? Darwin was in prison, charged with murder. Garret might soon be dead. Had I designed to vanquish father and son alike? "Your mother used you, Garret," I said. "She manipulated you. Just like she did me and North Anderson and who knows how many other men. I see that now. I know you're not fully to blame for what happened to Brooke. Or Tess."

He stayed silent.

"I think I know what happened," I said, keeping my tone even. "After your mom had the twins, she stopped the 'special relationship' you two had. She had somebody else to love. Brooke. And Tess. And when she moves on, she moves on. Cold. It's brutal. And it's painful."

"Billy didn't kill any cat," he said. "You deserve to know that. You care about him." He lifted one foot off the branch.

"Please," I said.

"You asked for this," he said.

I looked down and shook my head, trying to come up with words that would give Garret hope.

"Good-bye, Frank," Garret said.

I looked up just as Garret leapt off the branch. I closed my eyes, picturing Billy Fisk's face, bracing for the sound of his spinal column fracturing with the force of the rope. But, instead, I felt the full weight of Garret's body drop on top of me, knocking me to the ground. My head bounced off the dirt, leaving me dazed. The partially healed muscles in my back gave way, and a searing pain ripped through me.

Garret crouched over me, smiling, holding a knife in one hand and the end of the rope in the other. He lifted the noose off his neck, dropped it. "It wasn't tied to anything," he said. "The proverbial loose end. You should have checked."

I reached for my gun, but Garret dove toward me before I could get to it. I barely managed to raise my knee as he fell, burying it in his abdomen and knocking the air out of him.

The knife landed between us.

We both scrambled for it. His hand found it first. I grabbed his wrist and forced him onto his back. I nearly had him pinned when he rammed his head into my chin. I lost my grip on one of his arms, and he rammed an elbow into my face and pushed me off him.

He climbed on top of me and drove the knife downward, toward my chest. I caught hold of his wrist again. He was even stronger than I had imagined. The tip of the blade was getting closer.

"Those that I fight I do not hate" he said, pushing even harder on the knife. "Yeats. My favorite." His lip curled. "You had no business moving in on us, in the first place. If you had just left us alone…" He put everything he had behind the knife.

The tip came within a foot of my chest. There was only one move I could think to make. If I suddenly stopped struggling, Garret's momentum would carry him toward me. I could invert his wrist as he fell and bring him down on the blade. I didn't want to kill him, was horrified by the realization that I would be left the victor in a grotesque Oedipal tale, but I had no choice.

I felt myself getting weaker. The blade couldn't have been more than six inches from my chest. I had to act. I pushed with everything I had left against Garret, moving the blade a few inches further away, priming him for the fall. I looked into his eyes, reviewing the split-second move that would bury the blade in his chest, severing his aorta.

Just as I was about to let my arms give way, I heard a dull thud. Garret collapsed onto to the ground, moaning.

I looked up to find Billy standing over me, holding a bat. His face was a mixture of confusion and anger. I wasn't certain whether he was even conscious of what he was doing. He raised the bat over his head, his eyes thinning with rage as he stared back at me. I thought he was about to make sure I didn't send him off to any psych ward. But then his gaze shifted to Garret. He took a deep breath and reared back.

"Don't," I yelled. "It's not his fault."

Billy froze, the bat still cocked over his head.

I saw that his pupils had constricted to pinpoints. A rivulet of saliva ran from the corner of his mouth. Adrenaline had to be coursing through his blood vessels. This was the Billy I would have seen the moment he broke into a stranger's home, set fire to the Bishop estate, or strangled a cat. This was the Billy who had attacked Jason Sanderson's bullies. He was at one with his demons. "You're not a killer," I said. "Put the bat down."

He didn't respond.

I wasn't even sure he had heard me. I pulled my Browning Baby from the front pocket of my jeans. "Billy," I said, my voice shaking. "Put it down. Now."

He took a deep breath and arched his back.

I flicked the gun's safety to the off position, ready to fire. But I wasn't ready. Even as Billy snapped his wrists forward, I couldn't bring myself to pull the trigger.

The bat sailed past me and Garret, bouncing off a couple trees, landing in some leaves. Billy looked straight at me. "You got to trust someone," he said. Then he reached down and held out his hand for me.

As Candace comforted Julia, who was heaving with very real tears, the police took Garret away in cuffs.

The officers took some evidence along with them- things I'd found in Garret's closet before they arrived. Part of that evidence was an album filled with photographs of Julia. She didn't seem to be modeling, even though she looked model-perfect in every one. It seemed that Garret had taken the pictures without her knowledge. Some of them were benign: Julia walking around the grounds of the Nantucket estate, hailing a cab in Manhattan, riding a horse; Others were provocative: Julia sunbathing and swimming laps in a revealing bikini, pulling off a sweatshirt to reveal a see-through ribbed T-shirt, nursing Brooke. Still others crossed the line into the erotic: Julia sleeping naked, only half-covered by a white sheet. Julia in silhouette behind a steamed shower door. Julia, topless, shot through a window of the family's Manhattan penthouse. Julia locked in an embrace with North Anderson. And this last image, which still sends shivers up my spine and a pang of guilt through my heart: Julia and me kissing, inside my room at The Breakers.

The officers also took a stack of letters hidden deep in Garret's closet, each smelling of Julia's perfume, and each on the same heavy stock as the letter Claire Buckley had turned over to North Anderson and me. Garret's name, written across the front of the envelopes, was in the same delicate script.

The first of the letters I had opened was one from the middle of the stack. It had helped me see how blatantly Julia had romanced her own adoptive son: