I took a long, wide corridor toward the interview rooms. The fluorescent lights made my skin look cadaverous. The floor, a high-gloss, gray linoleum, translated every one of my steps into an ominous echo bouncing off bright white, cinder-block walls.

A guard met me at the end of the corridor and brought me to Billy Bishop, already seated at a small table, inside a six-by-eight-foot room with a glass door. He was wearing the standard-issue orange jumpsuit, with a black number stenciled across his chest. He stood up. He looked every bit as wiry as he had at Payne Whitney, but all the brashness had drained out of his posture. "I wish you had lent me that money," he said, forcing a grin. "I could have been long gone."

The guard and I exchanged reassuring glances, and he left. I stood just outside the room. "I'm glad you're all right," I said.

Billy made a display of looking around him. "I wouldn't say this is all right," he said.

I nodded toward the table. "Let's talk," I said.

He sat down. I took the seat opposite him. I noticed that the fingers of his hands were laced together so tightly that his knuckles had gone white.

"Strange place," he said, his voice suddenly a sixteen-year-old's, full of worry.

"It is." I paused. "Tell me how you're doing."

"How am I doing? I'm done," he said, his eyes showing none of their old fire. "Win won."

"Not yet," I said. "We're still working."

He closed his eyes and nodded. "They have me in protective custody, because I'm accused of hurting… killing a baby. I guess that ranks me with the guys who like sex with kids. If they could get at me, they'd-" He stopped and looked straight into my eyes.

Being imprisoned is more stressful than many men can stand. But being imprisoned as a pariah, a target, makes everything else look tame. "I want to ask you straight out," I said. "Did you have anything to do with what happened to Brooke or Tess?"

He kept looking right at me, never blinking, and shook his head.

"You didn't," I said. I wanted him to speak the words.

"I felt bad for the twins," he said. "They were born at the wrong time, into the wrong family. Like me, losing my parents. I didn't have any desire to hurt them."

I nodded. "I'm going to help find an attorney to represent you," I said. "In the meantime, you've got to try to keep your mind busy while you're in here. And you've got to try to stay hopeful."

"That's a long yard," he said. "Game's about played, don't you think?"

"It's not over. I promise you."

Billy's eyes filled up. He looked away while he struggled to hold back his tears. Then he took a deep breath and looked back at me. "I've got one idea," he said. "It's my last shot, or I wouldn't even mention it."

"What's that?"

"If Garret saw something the night Brooke was murdered, something about Darwin, would his word mean anything in court? Would a jury ever believe what he had to say?"

I thought about all the circumstantial evidence linking Darwin Bishop to the crime. An eyewitness, especially Bishop's son, might well be enough to make jurors believe Billy had been wrongly accused. "I think his testimony could change everything," I said.

"You should ask him, then," Billy said.

"I did," I said.

"That was before they caught me. Ask him again."

"Why don't you tell me?" I said. "What will Garret say that he saw? He must have told you."

Billy shook his head. "That's not up to me to talk about."

I wasn't sure why Billy would maintain a code of silence around something that might get him off charges of attempted murder and murder. "Why not? Why can't you talk about it?"

"Because I figure there's a good chance the jury won't budge, even with Garret's testimony, and then I'll get put away for life, and he'll be all alone with the devil. Just Garret and Darwin. If it were me, I don't think I'd take that risk. I mean, we're not that close. I'm not his real brother. And I've done some rotten things since I moved in with him. The stealing and all that. He would have been better off without me there."

My heart went out to Billy at that moment. He had lost his family in Russia and hadn't ever really been a full member of the Bishop family. Julia hadn't really favored his adoption, after all. Maybe that was part of the reason he'd started getting into trouble in the first place. "I'll ask Garret to think about it," I said. "You should ask him, too. Because it really could turn the key and get you out of here."

He nodded to himself, glanced at me, then looked down at the table. "If I did get released…" he started, then stopped short.

"Go on," I encouraged him. I was glad he could at least entertain the possibility that he'd go free.

"Nothing," he said. "It's stupid."

"Try me," I said.

He just shrugged.

"I've said more stupid things in my life than I can count," I assured him. "You'll never catch up."

That got him to smile. He glanced at me again, a little longer this time. "Well, if I ever did get out of here, I wouldn't have anywhere to go. They'd never take me back home." He cleared his throat. "Not that I'd go there, anyway."

"That can all get worked out," I said. "Between the Department of Social Services and Nantucket Family Services there are…"

"What I'm getting at is… Well, maybe I could kind of crash with you a while," he said. " 'Cause I think I could be different than the way I've been. If I had someone around I trusted. You know?" He looked at me, for my reaction.

I was slow to respond because at least half my mind was occupied with thoughts of Billy Fisk, how things might have been different for him if I'd been willing to go out on a limb.

Billy looked embarrassed. "It is a stupid idea. I mean…"

"I'd be willing to give it a try," I said.

"You would?" His voice was equal parts surprise, doubt, and relief.

"Sure," I said. "Why not? What have we got to lose?"

Billy and I said our good-byes, and I headed out of the prison. A prison guard friend of Anderson 's escorted me to a back exit so I could circle around to my car without being hounded by the media. "They'll be waiting for you," he explained, handing over copies of the Boston Globe and Boston Herald. Both papers, apparently worried about exhausting their readers' appetites for the Bishop family saga, had run stories about me. The headlines were typical tabloid trash: "Doc in Hostage Drama Back for Billionaire Babies" and "He Doesn't Shrink From Murder." The photographs of me that accompanied the articles had been shot during my testimony years ago in Trevor Lucas's very public murder trial.

All in all, I knew the coverage wasn't a bad thing. The media would be primed to listen to the message about Billy that Anderson and I hoped to get out. I just had to be careful to pull the trigger at the right time.

It was 4:10 a.m. En route home, I called the chemistry laboratory at Mass General to check on Tess's blood work. The laboratory technician told me the toxic screen had been negative; no new substance had been found in the baby's bloodstream. That ruled out Julia having slipped Tess anything to slow her breathing-at least anything recognizable by routine testing.

I called North Anderson next. He'd been in touch with Art Fields about the prints Leona had lifted from inside the prescription bottle. Three individuals-including Darwin Bishop, but not Billy Bishop-had touched the inner surface. No surprises there. "I would guess the other sets belong to Julia and maybe to the pharmacist who filled the prescription," Anderson said. "So that's another chink in the armor of Harrigan's case against Billy." He paused. "How did your visit go with him? They let you in, didn't they?"

"I just finished," I said.

"How does he look to you? Is he holding up?"