I PAGED THROUGH MY FRESHMAN yearbook after I got home, searching for someone with the initials PF. I went carefully through each grade, all the teachers, all the staff. It was strange to see how each individual looked, boiled down to a single shot. Some of my classmates had already transformed within the space of less than a year into someone almost completely different, while others had never really looked like their photograph to begin with—the image missing some essential aspect, flattening them into a pancake version of themselves.

The only one with the initials PF was Penelope Fetts, a junior with shiny dark hair and a wide gap between her front teeth. While I was trying to be open-minded, the birth control pills in Anna’s locker seemed to squarely rule Penelope out.

I did a second sweep through the book, to see if I’d missed anyone. This time, I lingered for a moment when I got to the photographs of me and Anna, which were, as always, side by side. Even in black-and-white, Anna glowed with that wide, unmistakable smile, like a child who’d just been handed a warm puppy. Next to her, I looked sullen, watchful, like I was deciding what I wanted more: to vanish into thin air or to kick the photographer in the shins. Our parents had laughed when they’d seen the photos. “There it is,” they’d said. “They got you both.”

Neither of us appeared in any other photographs. Nick, I noticed, showed up three times—his official school picture, jumping to make a shot in a game, and then in the back row of the basketball team photo. It was only in this last photograph that he was smiling, his teeth shining a brilliant white, a hint of dimple in his left cheek.

It was distracting, that dimple. It really was.