Mercedes jerks her bag out of my hand. She walks to the yellow railing along the school driveway and perches on the top bar. “Half sisters,” she says, and pulls her phone out of her pocket.

I pause. I don’t think I’m coordinated enough to sit balanced on that railing, so I collapse on the curb instead. I glance over at Mercedes. Her face is partially hidden by her hair, but her expression is a mixture of annoyance and sadness and fury and maybe—or I might be imagining it—a bit of joy.

I hear a car, but it’s not my mom’s new minivan. Mercedes looks up too. A tall boy climbs in and the car drives away.

Three kids emerge from the multipurpose room, laughing and talking. A black truck stops and the boys clamber inside. One of them calls to her. Mercedes pretends not to notice.

I check my phone. Four minutes after four. My mom is late to pick me up. I try not to panic. Starting in third grade, I used to get panic attacks at least once a week. Sometimes I cried; a couple times I even threw up. When it happened in school, I almost always told the teacher I was dying. The school nurse would call my mom and she’d have to explain, “She’s not sick. She’s having an anxiety attack.” Panic episode, she started to call them. Because, technically, she says, they don’t attack me. My mom says that if I start feeling worried, I should count backward from ten and then make a plan. Ten, nine, eight. A plan. My plan is to call if she doesn’t show up in six more minutes.

I guess Mercedes’s ride is late, too. The two of us sit ten feet apart, but we might as well be a million miles apart.

I wonder who will pick her up. Her mom? Does she have a stepdad, like I do? She said she has a brother. I open my mouth to ask her. My phone pings. It’s my mom texting me that Bob is picking me up. I’m so surprised, I call her. “Why can’t you come?” I ask. Even I can hear the whining in my voice. She explains that Bob’s getting Kenny from soccer practice and Poppy View Middle School is on the way home. After twelve years of being an only child, how did I end up with a stepfather who picks me up from school? And stepbrothers?

And now a half sister?

Bob arrives a few minutes later. I climb in the front seat. As we drive away, Mercedes sits by herself, alone, still waiting.

“Is that a new friend?” Bob asks.

I shake my head. “Just a girl in my grade.”