The gymnasium flickers with strobe lights, the DJ plays one rap song about butts after another, and my twin sister is looking really weird as she dances. I’ve been sitting here with my back pressed against the metal planks of the folded-up bleachers for so long that my bones are starting to hurt and I have to keep shifting positions, but she’s still bopping back and forth on the balls of her feet, her body all crooked, totally oblivious. I can make her out pretty well from here because she’s at the back of the crowd and there’s an arc of space between her and the rest of them, an arc like we drew with our protractors today in math class. She keeps pushing the arc forward as she dances slowly toward the stage and then gets shoved back again when some boy or another with a backwards baseball cap trudges past her, but wherever she goes that radius always follows.

It’s kind of dark, and I’m too far away to see everyone’s faces, and most of the time they’re not looking back here anyway. But every now and then, a head or two along the edge of the arc turns around and looks at my sister, and I know what to imagine. I know those stupid faces with their stupid expressions falling all over everyone else. I know how they’re looking at her and how they’re laughing. Most of all, I know how much I hate these faces for her, how much they feel like my own, and how little she seems to notice or care.

I’m Jessica, and my sister is Elizabeth. When people hear that, they say, Oh, just like the Sweet Valley Twins! Except I’m not the popular one, she’s not the smart one, and neither of us is blonde or pretty. We’re not even identical. For one thing, Elizabeth is developing faster than me. Mom always tries to be nice about it, but I wish she’d pretend not to notice. A few weeks ago, she went shopping with Elizabeth for a bra and invited me to come along. I said I didn’t want to go, but she still came back home with some training bras for me that are just like cut-off undershirts, only with more lace on them. I told her I didn’t want them, they looked really lame sitting next to Elizabeth’s Maidenforms in our drawer, and I put them back in the bag and threw it on her bed, all ungracious. But maybe it was good that I did that, because the next day she showed me how to shave my legs, which is something that Elizabeth doesn’t do because it’s too dangerous.

Elizabeth goes to a different school than me because she needs special classes. I go to Potomac Middle School (PMS!), which is in our neighborhood, but she gets bused out to Woodard Junior High, where they’ve got a learning-assistance center. Woodard is where we are tonight. It’s only the second time I’ve been here. The last time I came was on Elizabeth’s first day of school two months ago, when Mom drove us in an hour early so I could show her how to use her combination lock and make sure she knew where homeroom was. There were hardly any students then, just big echoey halls like I had never seen. Now it doesn’t look much different than Potomac: girls gossiping, crying, smacking on more layers of flavored lip-gloss; boys huddling in corners, headbanging, getting into fistfights. I can even tell the popular kids from the preppies from the nerds from the goths from the hippies from the jocks from the skaters and everyone outside and in between, just by watching.

Elizabeth probably knows most of the nice community-service types here. This one girl came up to her when we were buying our tickets and started asking her all these chirpy questions. She had really big boobs, bigger than Elizabeth’s and Mom’s put together, and when she realized that I was Elizabeth’s twin sister, she introduced herself as Megan Mackelby. Megan said she helped out at Elizabeth’s lunch table three times a week. I pictured her pushing wheelchairs around a cafeteria, wiping up drool, making one chirpy conversation after another, and I was glad that I don’t have to do anything like that at my school. Last year, when Elizabeth and I were at Potomac Elementary together, I didn’t even like stopping by to see her in the special-needs room, and after her teacher had to keep one of the boys from rubbing up against me for the third time, no one ever expected me to. Sometimes I wonder how Elizabeth deals.

* * *

Our favorite things to play used to be library, house, and school, but I never want to play them anymore. Now, library is where people pass dirty notes, house is where everyone fights, and school is just a bunch of bells and lockers. So lately all we do is put on music. Elizabeth has a silver boom box with a plastic microphone attached, and sometimes we sing into it, and sometimes we just swing it around on its cord and dance or laugh. When Elizabeth really likes a song, her right hand lifts and starts twitching around about six inches from her nose like it’s possessed. I jump up and down and do cartwheels. We also do our exercises to music, lying side by side on the living-room carpet. I have ten sets of each muscle group every other night for MarVaTeens, and Elizabeth has calf and hamstring stretches her physical therapist gives her so she won’t have to be so bent up. I keep telling Mom that Elizabeth always cheats, but I am just irritating, she is doing what she can.

Mom thinks I’m the best one to help Elizabeth with lots of things, which is why I’m at this dance. She brought it up real last-minute. We were eating takeout Dungeness crabs for dinner in the kitchen, Dad was away, and the broken carcasses were sprawled all over the newspapered table.

“You two enjoy your music together. I thought this would be a nice sister-sister activity.”

“But Twin Peaks is on TV tonight.”

“And that’s more important than doing something for your sister?”

“What do you mean ‘doing something for your sister’? Elizabeth doesn’t even care. It’s your idea.”

“Jessica, stop. You get to go to your school dances. Don’t you think she should be able to go to hers too?”

“She can go without me.”

“Jessica.”

“What? She can. She’s just as good at it as me.”

Mom put down her wooden mallet, and I could feel her eyes on me. “Listen, do you want to tell me why you have such trouble doing anything nice for anyone lately?”

“It’s not the same, Mom. I like different things now. It isn’t like we used to be.”

“Jessica, you’re her best friend. Elizabeth didn’t choose to be like this.”

“Neither did I!” I stood up as I shouted this, throwing my crumpled napkin onto the pile of fractured shells, tears puddling up in my eyes, and stormed upstairs into my room to change.

* * *

There are eight obvious little cuts on my fingers from the crabs, but I keep inspecting my hands for more, and when it seems like I’ve done that for long enough, I try squeezing and rubbing different sections of my pink Hypercolor T-shirt to see if it’ll change to blue. I’m wearing my coolest outfit because I wanted everyone to think better of Elizabeth, but here in the shadows I guess it’s not making any difference. I was dancing with Elizabeth before, but then a slow song came on and I heard someone mutter lesbian retards, and I decided to go sit down. Maybe no one said it, maybe it’s just what went through my head. Anyhow, Elizabeth kept dancing away, and she hasn’t looked back at me since.

Not until now. The electric slide just came on, and everyone is starting to form themselves into little lines. I hate the song, and I hate the stupid dance everyone’s supposed to do together. But when I see Elizabeth, edged to the far wall by the first wave of side steps, turn toward me in confusion, I’m glad I know how to do it. I push myself up from the waxy floor and join her on the sidelines.

“Ok, here’s how it goes.” I stand facing her and wait for the beat. “Step-slide, step-slide, step, clap.” We start to move to my left, to her right, and she gets everything wrong but the clap. Then her hand starts to twitch like crazy.