“You’ve heard of Anne Frank, right?”

I had, of course. I had not only read The Diary of Anne Frank, but when I was twelve, my parents took me to the house in Amsterdam where she hid from the Nazis. The two parts I remember best: One, the moveable bookcase that hid the stairs up to the secret attic where the Frank family stayed. Two, the Anne Frank quote you see as you leave this somber memorial: “Despite everything, I believe that people are really good at heart.”

“Of course, I’ve heard of her,” I said.

“There was another girl. A thirteen-year-old Polish girl named Lizzy Sobek who escaped from Auschwitz and worked for the resistance.”

The name rang a bell. “I remember reading something about her.”

“Me too. We talked a little about her in eighth-grade history. Lizzy Sobek’s family was slaughtered in Auschwitz, but somehow she escaped. She is credited with saving hundreds of lives. In one documented case, Lizzy ran a February raid that slowed down a cargo train loaded with Jews heading for the death camps. More than fifty people escaped into the snowy woods—almost all under the age of fifteen. And some of those she saved claim”—Ema stopped, took a deep breath—“that when they escaped, they saw butterflies.”

I swallowed. “Butterflies?”

She nodded. “In February. In Poland. Butterflies. Hundreds of them leading them to safety.”

I just sat there.

“Lizzy Sobek became known as the Butterfly.”

I may have been shaking my head, but I can’t swear to it. I knew that we were both thinking the same thing. Butterfly—like on those T-shirts in the old photograph, at my father’s gravesite, on the tombstone in Bat Lady’s backyard. It couldn’t be a coincidence.

“Lizzy Sobek,” I said—and suddenly my blood went cold again. “Lizzy could be short for Elizabeth.”

“It was,” Ema said.

Elizabeth Sobek. E.S. The initials on that tombstone. Another coincidence? I asked the obvious question: “What became of Lizzy Sobek?”

“That’s the thing,” Ema said. “No one really knows. The vast majority of scholars believe that she was captured during a raid to free a group of children starving to death near Lodz. They believe that she and other resistance fighters were shot and buried in a mass grave, probably in 1944. But there has never been any proof.”

“A childhood lost for children,” I said. “That phrase makes more sense now.”

Ema nodded. “There’s more.”

I waited. The restaurant was bustling. People coming and going, enjoying their food, laughing or texting or whatever it is people do at restaurants. But for us, they were gone now. The room was just this booth—just Ema and me and the ghost of some brave, long-dead girl named Lizzy Sobek.

“I did all kinds of searches on those numbers—the ones on the bottom of the tombstone and on that license plate,” Ema said. “The A30432. But I came up with nothing.”

I sat very still. If she had ended up with nothing, there wouldn’t be tears in her eyes.

“So I read more about Lizzy Sobek,” Ema said, reaching into her pocket and pulling out a piece of paper. “I found one of those Q and A sites on her life.” She unfolded the paper and slid it across the table.

I took it from her. Ema looked off. I turned my attention to the paper:

Question 8: What was Lizzy Sobek’s concentration camp tattoo ID number?

It remains unknown. Most people mistakenly believe that every person in a Nazi concentration camp was tattooed, but in truth, the Auschwitz concentration camp complex (including Auschwitz 1, Auschwitz-Birkenau, and Monowitz) was the only location in which prisoners were systematically tattooed during the Holocaust. On September 12, 1942, Lizzy, along with her father, Samuel, her mother, Esther, and her brother, Emmanuel, boarded a transport to Auschwitz-Birkenau. The transport arrived in Auschwitz on September 13, 1942, with 1,121 Jews on board. Men and women were separated. The women selected from this transport, including Lizzy and Esther, were marked with tattoos between the numbers A-30380 and A-30615. Records indicating their exact numbers have not been preserved, so to this day, the number Lizzy Sobek bore on her forearm remains a mystery.

I looked up at Ema and now I had tears in my eyes too. “Have we solved this particular mystery?”

“We may have.”

“Which leads to another.”

Ema nodded. “How would Bat Lady know the exact same number?”

“And why would she have a tombstone for her in her backyard?”

“Unless . . .”

Ema stopped. We both knew what she was thinking, but I don’t think either of us was ready to say it out loud. Maybe we had solved a mystery deeper than a tattoo number. Maybe, after all these years, we had solved the mystery of what really happened to Lizzy Sobek.

Chapter 17

THE NEXT MORNING, I called my mother at the Coddington Institute. The operator said, “Please hold.”

There were two rings and then the phone was picked up. “Mickey?”

It wasn’t my mother. It was the rehab’s director, Christine Shippee. “I want to talk to my mother.”

“And I want to take a shower with Brad Pitt,” she said. “Sorry, I told you, no contact.”

“You can’t just cut her off from me.”

“Uh, yeah, Mickey, I can. Speaking of which, we need to talk. Do you know what an enabler is?”

Again with that question. “I didn’t give her the drugs.”

“No, but you’re being a candy ass about this. You need to be tougher on her.”

“You don’t know what she’s been through.”

“Sure I do,” she said as though stifling a yawn. “Her husband died. Her only son is growing up. She has no prospects. She is scared and lonely and depressed. What, you think your mother’s the only one in here with a sob story?”

“Your sympathy,” I said, “is overwhelming. No wonder the patients love you.”

“I was one of them, Mickey. A manipulative addict. I know how it works. Come by next week and we’ll talk more. In the meantime, get to school.”

She hung up.

At school, most of the morning was taken up with an assembly program. I don’t really remember much of what was being said. Two local politicians tried to “relate” to us, which made for serious condescension and boredom. I spent the time glancing around the room and locking eyes with Rachel.

When lunchtime came, I sat at what was fast becoming our usual table with Ema. Spoon was nowhere to be found. Ema and I tried, for once, to talk about the new movie releases or what music we liked or what TV shows were our favorites—but we kept steering back to the Holocaust and a heroic girl named Lizzy Sobek.