It was mid-October, two days after my birthday, when the girl began living in my bedroom. That day, we came home from school to see baba lugging a duffel bag into my room, dragging it across the hardwood floor by its handle. The metal zipper carved a thin white line into the wood. I saw the outline of a slim, pale nose before he closed the door. A flash of long black hair. He said Rafa and I would have to share a room from now on. Just that.

No explanation.

“But, baba, my stuff,” I said, thinking about my books, my gel pens, my watercolors, the turquoise seahorse Lena saw me admiring in a storefront window and bought with her own allowance for my birthday. They were all on my desk. If he would just let me grab them.

“Stop,” he said, pressing his back against my bedroom door. “Later.” His arms were crossed like a bodyguard’s, a vein crawling up his forearm like a green worm.

Mama pretended not to see her. When the girl walked into the kitchen, taking a bag of potato chips from the cupboard before returning to my room, mama would look past her. Sometimes mama bumped into her, stumbling into the side of a table and saying Damn it or Cabrona but never Sorry. The first time I saw her come out of my room, I looked at her belly, which looked as round and tight as a small watermelon, the fabric of her shirt—my tie-dyed shirt, I realized—stretching thin around her belly button.

“Isn’t that mine?” I asked.

But she hurried back into my room before she could answer. At night, when it was late and Rafa’s breath would steady and I could tell he was asleep, I wondered what the slightest pinprick of one of mama’s sewing needles would do, if air would burst out of her belly loudly like a whoopee cushion. If she would pop or disappear altogether. Then I could have my room back.

“Do you know who she is?” I asked Rafa one night before bed. I thought she might be one of baba’s cousins visiting from Egypt, but I was not sure.

He did not answer.

I nudged him. “Rafa.”

“What?”

“The girl. You know who she is?”

He turned over and faced me. “The bruja? No. Mama says if you make eye contact with a bruja, you’ll turn into one.” Then he groaned. “Sofia, you woke me up.”

“Okay, okay, go back to sleep.”

We turned away from each other, and again I heard his breath steady.

* * *

Tonight, a few minutes after mama turns off the overhead light, I hear it, the knocking, and my eyes flicker open, and there, at the window, is a man. It is dark out and I can close my eyes to make him gone, simple as that, but I hear it and cannot stop hearing it. Knock, knock. Knuckles on glass.

“Eyes down. You’re asleep,” mama says, whispering, and her lips barely move. “Look like it.”

“Can—” I start.

“Sleep. He’ll leave soon.”

I want to ask her if she would honk the horn because it worked last time. But he just knocks and knocks and continues knocking. Then he speaks:

“Just wanted to know if you’re looking to kick it or something. If you’re looking to hang out. Shit, I’d pay. Only if you’re good, though—you’d have to be good. I can see you, by the way. Three of you, at least, in there. You could be a baby sugar. Or, uh, no, that’s not it. A sugar baby. Sorry, I’m buzzed. How old is the girl, by the way? Is she a woman yet?”

Mama clenches her jaw.

Am I a woman yet? I want to ask mama but she would tell me to sleep.

* * *

One night at home, I waited twenty whole minutes for Rafa to fall asleep. I wanted to ask the girl who she was, why she was here. I looked over at my brother, curled up on his side, holding a plastic dinosaur to his chest with his fingers wrapped around its torso. Drool dripped off the side of his mouth, pooling on his pillow like a small pond. I grabbed a tissue from the bedside table and wiped it off. Then I slipped out of bed and walked down the hall, past the framed pictures of abuelo, abuela, teta, and giddo, looking down at the hardwood floor to avoid their eye contact.

My bedroom door was wide open. The window was open, too, with the blackout curtains drawn all the way back. The pale moonlight poured in through the windows like milk, drenching my walls, my desk, my rug like I was standing in a bowl of it.

I walked toward my bed. No one there. Nothing on it, either, except for a deflated bag of potato chips, a few crumbs spilling out on my quilt. I brushed them off onto the floor. We were never allowed to have food in our rooms. It was one of baba’s rules.

“Yes?”

I turned around. She was behind me.

“Oh,” I whispered. “Sorry.”

The girl’s hair was wrapped into a bun, a few strands uncollected, glossy in the milk light. Her skin seemed to glow from the inside, like someone had placed a tea candle on her tongue and she balanced it there, behind her lips. She was wearing my pajamas, her round stomach poking out between the shirt and pants.

“Sleepwalking?” she asked.

I turned to leave.

“No,” she said, and grabbed my wrist. “Stay. For a minute, I just—” She ran her hand through her hair, letting it down. “You’re what, thirteen?” she asked, stepping closer to me, pushing a loose hair behind her ear.

“Twelve,” I said, my voice smaller than I would have liked.

“Twelve,” she repeated, trailing off. She looked down at her hand, still wrapped around my wrist. She let go. “Sorry. Didn’t mean to grab you.”

I looked at the door.

“Well, I’m you plus . . .” She counted in her head. “Plus nine.” She laughed. “I know, I’m short. It makes me look younger than I am.” She pressed her lips into a tight smile, her eyes boring into mine like a hook into a fish.

I pinched the rug between my toes. “My mom says it’s good to look young.”

“Well, your mom doesn’t like me one bit, so . . .” She looked down at her stomach. “Oh!” she whispered. “I have an idea. Give me your hand.”

“My hand?”

“Trust me.”

“I don’t know you.”

“We live in the same house.”

She took my hand. I let out a whimper.

“Loose, girl, loosen up,” she said, shaking my hand until it was limp, then setting it on her stomach. Warm met cold.

“See? Nothing bad. Just life under there. Small life.”

I pulled my hand back. “I’m going to go now.”

I ran back to Rafa’s room and climbed into his bed. It was one of our last nights living with baba and it ended like this: Rafa next to me, a stegosaurus, T. rex, and velociraptor in the space between us. Mama in our parents’ bedroom. Baba on the couch. The girl in my room underneath my yellow patched quilt blooming me a half sister.