He knocked Iris out with drugs.

There was a sticky substance on her head.

He turned into a monster.

She played dead, and he buried her.

I suddenly felt terror, as if I had seen him transform into someone evil, just the way Iris had. The way my sister must have.

Who had turned into a monster and killed her?

Who had dropped a gold charm and a blue-gray feather?

How had the gold dust gotten there?

The name I didn’t want to think about flashed through my mind, over and over.

“I have an idea,” Iris said, interrupting my thoughts.

“What?”

“Tell me one thing about the day Eloise went missing. Not the whole day, okay? Just one incident that stands out. Or one word! Even if you think it has nothing to do with her being taken. Just something that really sticks in your mind. Something that made you really nervous, and you didn’t like the way you felt. Or . . . something you loved. That the two of you loved.”

I gave her a look full of skepticism.

“Oli, maybe there’s something in common with the day Hayley and I were taken. It might jog my memory,” she said.

“Like whoever took you has a signature?” I asked. “Something he can’t help doing that will tell us who he is?”

“Exactly,” Iris said.

Then I felt excited, because the possibility of uncovering the murderer’s identity was the first bit of hope we’d had so far.

The only thing was, I knew how painful it would be to remember that horrific day when my sister disappeared.

“Tell me,” Iris said.

I didn’t have to think very hard because everything about that day was emblazoned in my heart.

“Birds,” I said, picturing the early-morning quiet, the net in the thicket. “We went birding with our nature club that morning.” Matt, Fitch, Chris, Adalyn, Eloise, and me.

Eloise and I had woken up before dawn, when it was still dark and cold, the grass and leaves tinged silver with an early frost. Matt, Chris, and Fitch were waiting outside our house in Matt’s Jeep. Matt drove us to the highest elevation in the seven-hundred-acre Braided Woods. We met Adalyn in the parking lot, then trekked down a narrow trail into a hollow that spread into the grasslands.

Adalyn was beautiful, with golden-brown eyes and wavy dark hair that she wore pulled back in a thick ponytail. We’d known each other since fourth grade, when her family had moved here from Ohio, and we’d become friends right away. Adalyn was an unlikely birder—she wasn’t really into nature. She didn’t like walking through narrow trails where there might be mud, or branches that would brush up against her, or bugs or snakes. She loved pretty things, had impeccable style, dreamed of being a fashion designer. She’d joined the nature club to be a good friend to me, but also because she had a slight crush on Fitch. The two of them walked side by side that morning. I ended up walking next to Matt, and Eloise next to Chris.

I tripped over a root, and Matt grabbed my hand just long enough to steady me. I felt my heart flip. He looked at me with those gold-flecked blue eyes and smiled before he let go of my hand.

Chris and Eloise were talking softly, as they had up on the roof of Ocean House a few months before. Chris carried an expensive Swarovski telescope that probably cost as much as some of the old used cars our classmates drove.

The six of us came to the blind our group had built to hide in while watching a net. The net was made of threads that formed inch-squared openings that would catch but not harm the birds, and was assembled in a fifty-foot-long curve—like a giant badminton net. Chris set up the telescope on a tripod, through which we could watch far-off birds and other wildlife.

October 9 was toward the end of fall migration, when birds flew down from northern Canada, stopping in New England on their way to a warmer climate. That autumn was especially exciting because it was an irruption year—when certain species not usually seen on the Connecticut shoreline arrived in impressive numbers.

We were spotting white-winged crossbills, evening grosbeaks, redpolls, and red-breasted nuthatches. None of us had ever seen crossbills before; they fed on the seeds of closed spruce cones, and we heard them up above, their bills clicking as they cracked open the cones.

As we stood in the blind in the gray predawn light, I saw Eloise lean close to Chris, the two of them taking turns looking through the telescope. He pointed it toward the sky. She pressed her eye to the scope and I knew she was looking up at Venus glowing beside the morning moon—the last quarter, suspended above the horizon just before sunrise. He was whispering to her. She laughed and nodded, and I heard her say, “Definitely.”

I turned away from them. I faced the net and could see that it had caught several birds. A storm the night before had caused a “fallout”—more migrants than usual, landing to rest and feed during their long flight north.