“Who is this?” she asks.

I pull myself onto the bathroom counter and sit leaning against the mirror so I can’t see my face—her face—anymore. “Mercedes. Your half sister.” I spit out the words, trying to sound as annoyed as possible. The words feel weird in my mouth. “Do you have a bike?” I repeat.

“Um, yes.”

Neither of us says anything.

“Why?”

“Do you know Laurel Park?” I ask. “Meet me there in thirty minutes.”

“The park on the hill? I guess. Why?”

Ugh. She is so exasperating. “Can you meet me or not?”

“I’ll have to ask my mom.”

“Fine, go ask her.” Cristina always lets me do whatever I want. And Mom’s never home to decide one way or the other. “And then meet me there. Twenty minutes.”

I hang up before she can say anything else. After I gulp down a plate of vegetable stir-fry, I grab my helmet from the back closet.

“Do you need any money?” Cristina asks as I buckle my helmet. Cristina has cash that’s for me and Tristan. Kind of like allowance. Candy, new earrings, a yo-yo. Little things like that. We might not ever have Mom around, but we can buy just about anything we want.

“Sure,” I say, and she hands me a twenty. Always take money when it’s offered, that’s my advice.

I get sweaty biking up the hill to Laurel Park. The wind whipping at my back feels good. It’s just a little park with a swing set, a couple picnic tables, an enormous live oak tree. I bring Tristan here sometimes, although he prefers the bigger playgrounds—or the roller coasters and Speeding Saucers at the Boardwalk, if Cristina will take him. He loves adventure. He’s like me that way.

Mattie’s sitting on top of a picnic table when I arrive. I drop my bike next to hers and sit beside her.

“Matilde,” I say because I can already tell it annoys her.

“Hi, Mercedes.”

Silence.

Suddenly I’m not even sure why I wanted her to meet me.

She nervously snaps and unsnaps the buckle on her helmet. “What do you want?” she asks.

“I hope you didn’t tell anyone. About us.”

A look of panic or maybe pain shoots across her face. And then she looks away. I almost feel bad.

“I mean,” I say, trying not to sound as cruel as I feel, “it’s no one else’s business, right?”

She shakes her head.

“Did you tell your mom?”

She shakes her head again. I’m so relieved, I almost smile.

“I just want to make sure you’re not planning on telling everyone.”