(Start here.) (Or just go backwards.)

I got my arms around her, and shifted her so she wasn’t on broken glass, and dragged her out until we were on the tunnel floor, away from the box, near the wall. She had a thin tracing of blood on her forehead from where the glass flecks had cut her.

She was breathing—that’s what I kept reminding myself, as I tried to move her away from the glass: she’s breathing. And her face was still, not twisted and angry like it had been, just pale and gray. Her eyes were closed, and as I watched her, silver washed across her skin like a spreading stain.

I sat on the floor next to her and shook her shoulder. “Mom?”

And here is the absolutely infuriating and excellent thing about my mother: she fluttered open her eyes and she started to laugh.

“Mom! It’s not funny!”

“I’m sorry.” Her voice was weak and her eyes were teary, but you could tell from her face that she was just trying not to laugh again.

“Mom, this is serious!”

“I know, sweetheart, but your hair.”

I touched my stupid hat, and took it off.

“Oh my,” she whispered. She reached over and rested her cold hand on mine. “Alyssa.” She closed her eyes again as though she was falling asleep.

“Mom.” I shook her shoulder. “You have to wake up. Everything is crazy, and Mom: what about if A, then B?”

She wrinkled her forehead as though she was trying to remember, though she didn’t open her eyes. “Then if not B, not A? Is this a logic test?”

“Mom!” I looked around. I didn’t even know how to get us out of there. “You were writing equations, right? And you left something in the house before they came and got you or whatever. The shadows, Mom? And Phoebe sent me the equation, but that’s all it says, Mom, and it’s not helping. What are we supposed to do?” Her eyes started closing again, and I shook her shoulder, hard. “It’s important.”

“Oh!” And any laughter drained from her face. She tried to open her eyes and sit up. “What’s happened?” She was really weak.

“I don’t know—they’re these shadows, and there used to be loopholes, and—just tell me how to stop it, Mom, can you?”

“Oh Alyssa.” She looked at me, her eyes searching my face. “I’m so sorry. You weren’t supposed to—.”

“Yeah, well the lizards found me.”

“The lizards,” she whispered, and she almost smiled again. “They thought that was a good idea.” She tried to shift onto her side so she could see me better, but she couldn’t even quite move herself. “I told them to leave you alone, but they said you could do it.”

I looked down. “I betrayed everyone,” I whispered.

“Alyssa.” She touched me again. Her hand was really cold. “It’s not about that.”

“What is it about?” I asked. “What are we supposed to do? How does any of it work? Mom, you have to tell me what you know. What happened to Dad?”

She closed her eyes again, like even hearing that hurt. I tried to listen for sounds in the hallway, for something, I didn’t know what. But it was quiet in an echoing, terribly way, like we were the only ones down there and the air was slowly emptying out. “It’s sort of funny,” she said. “It started out as a logic problem, if you can believe that,” and she almost smiled.

“Yeah, Mom, that’s actually not so funny, and also: what are you talking about?”

She sighed. “I’m talking about how it started. Oh Alyssa. It was so long ago. Your dad and I, remember how we used to work together? This was years ago.” Her eyelids fluttered, like she was sick, but she kept talking, pausing to catch her breath. “You know—I work with morality, and your father is…was, more of an expert on logic. Your father was so impossible,” and she smiled, just happy to be remembering him. I leaned in closer to hear her. Her voice was getting thready and strange. Her skin was getting more and more glittery, and I wanted her to keep talking, but I thought we needed to get outside too. The shadows couldn’t really be outside, could they? Weren’t they not OK in the sun except for that one with red hair? But I didn’t want her to stop talking. “We were at a conference, in Prague, which is such a lovely city!” Her voice sounded light and almost happy, like it hadn’t sounded in so, so long. “Your dad and I got to talking about how so many people participate in genocides, you know? Perfectly ordinary people, people who you think wouldn’t. People who later go on to be perfectly nice, they do terrible, terrible things. That’s how genocides work, there has to be participation or they don’t happen.” She stopped. She almost seemed to fall asleep, but then she started again. “Dad wondered about the…implications.” She breathed in and tried to keep talking. “If there were all these ordinary people who would participate, well, what about the other people? What about the people who didn’t participate?”

“The loopholes,” I said.

“Yes, the loopholes,” she said. “Just one person to help others escape. It…it changes things. And you know Dad.” Her voice was faint. Her eyes were closed. “What do you think Dad did?”

“He made it into an equation,” I said, because that’s what my dad did with everything. He loved writing equations.

The ghost of a smile was on my mom’s face. “Yes. He transcribed it into a logic problem. An if, then problem. If a genocide was unsuccessful, that meant someone had tried to stop it. And then he looked at the contrapositive. What would happen if no one had tried to stop it?”

“Then not A,” I said. “Then it wouldn’t be unsuccessful? I mean—.” I stopped. I got it. “If no one tried to stop it, then it would be successful. Like, totally successful.”

“Yes. He wrote that equation down, and—and it distressed him very much. He went for a walk.” Her voice got ragged and tight. “He called me from his cell phone, on his way back, to tell me to erase it, that it was a mistake. And that’s when….”

“That’s when he got hit by the car?” I said. “When he was trying to tell you?”

She nodded, exhausted. Her eyes filled with tears, and she was quiet. “And then, slowly at first, things started to happen. And they started to get worse. I thought it was just me. I thought it was the effects of mourning. And then the paper we were working on vanished somewhere. And somewhere along the way I realized,” she grabbed my arm with her hand, but she was so weak I hardly felt it. “I realized that it was connected. I should have known,” she said. “When he was writing out the equation, it felt like the room went dark.” She stopped talking.

“Mom, how do you reverse the equation?” I shook her shoulder. “Mom? How do you reverse a contrapositive? Can you just reverse it: If someone tried to stop it….”

“You can’t,” she said. “That’s not sufficient to make the opposite. You can’t undo logic,” she said. “It just…it just is.” Her head lolled back.

“OK, I have to get you out of here,” I said.

“Alyssa.” She smiled, but didn’t open her eyes. “Go. Don’t worry about me.”

“I’m not leaving you here. Come on, I’ll carry you. Stop laughing!” I took her arm, which felt way too limp, and put it around my shoulder, then tried to get my arm under her knees to stand her up. She was heavy. “OK, Mom, we’re going to stand up now. You have to hold on.”

“Alyssa.” She opened her eyes. Even they looked silvery and far away. “It’s OK, kid. All right?”

I tried to get my balance before I stood up with her. “No, it’s not OK, actually. It’s not. There’s too many people. There’s the guy from the store down by the bus station, and Officer Rivera, and the lady at the Laundromat—.”

“Who’s Officer Rivera?” she asked sleepily.

“Never mind. Mom, now hold on or—.”

“Just be good, sweetie.”

“Yeah,” I staggered. “OK. Promise. Now on the count of three—.”

“Alyssa!” She grabbed my arm with her weak hand. “You’re not listening!” Her voice strained, it seemed like she could barely keep talking.

“I’m listening, Mom. Now: one. Two.”

“Be good.”

“Three!” I stood up, and staggered there for a second, with my mom in my arms, and then one foot slid out from under me and we collapsed on the ground, scraping the wall on the way down.

My mom was on top of me, completely limp. I said, “Mom, get off of me,” for a while until I finally half shoved her, half rolled out from under her, then sat up, panting, while she lay on the ground, dirt scraped in her hair and across her pale silvery face. She looked like she was dead. I didn’t have the strength to lift her. I closed my eyes, and tried to remember what, if anything, could help me. “Lizards,” I whispered. But nothing came.

And then a heavy, warm hand touched my shoulder. I flinched around. “Adam,” I said.

“Come on,” he said. “Emily and Jacob snuck out to try to find Phoebe. I’m supposed to find you. But we have to go outside. They can be in sunlight now. They’re stronger, and they’re outside, and—wait. Is this your mother?”

“Yeah,” I said.

He looked down at us collapsed there on top of each other. He nodded, and then be bent down and put his giant arm underneath her, and heaved her up. She hung there, heavily. “OK,” he said, breathing hard under her weight. “Come on. We’ll go up together.”