elda kneels to pick up the punch card. Yolanda’s going wild behind her. But all Zelda hears is Brewster carrying on about how she shouldn’t trust anyone. He doesn’t know Elisa, though, does he? Of course he doesn’t. Despite their long years of friendship, Elisa’s never been to Zelda’s home, not once. But Zelda knows the girl. She knows she knows the girl. And this is not the Elisa she knows.

Elisa’s card waits in its slot, unpunched despite Elisa’s rapid exit from the locker room. A small detail, maybe, until you add it to everything that’s been going on at Occam over the past several days. Equipment under dust covers being wheeled out of F-1. Scientists shaking hands at coffee-and-doughnut farewells. A mixed mood that feels like the last week of senior year: excited, but fearful, and sad, too. Zelda can feel the whole building clenching as if for impact. Something big is happening today, and Elisa, it seems abruptly clear, has gotten herself entwined. And how does Zelda know this? It’d been right there in front of her all night, squeaking across the floors.

Elisa’s shoes. She’d been wearing ugly, gray, rubber-soled sneakers, built for running.

Zelda swipes up her card, punches it, and then, in an act that makes Yolanda spit acid, finds Elisa’s card and punches that, too. Punch cards, after all, are the first evidence to which Fleming will look to find out who is here and who’s not if something goes wrong. Zelda wheels around, bumping past Yolanda without apology, and hustles back in the direction of the labs. Go wrong? Her hunch is that a lot is going to go wrong, a whole lot, and very quickly.