Idlewild is a tiny, artsy Quaker high school in lower Manhattan. Students call their teachers by their first names, there are no grades, and every day begins with 20 minutes of contemplative silence in the Meetinghouse. It is during one of those meetings that an airplane hits the Twin Towers.

For two Idlewild outcasts, 9/11 serves as the first day of an intense, 18-month friendship. Fay is prickly, aloof, and obsessed with gay men; Nell is shy, sensitive, and obsessed with Fay. The two of them bond fiercely and spend all their waking hours giddily parsing their environment for homoerotic subtext. Then, during rehearsals for the fall play, they notice two sexually ambiguous boys who are potential candidates for their exclusive Invert Society. The pairs become mirrors of one another and drive each other to make choices that they'll regret for the rest of their lives.

Looking back on these events as adults, the estranged Fay and Nell trace that fateful school year, recalling backstage theater department intrigue, antiwar demonstrations, smutty fanfic written over AIM and a shared dial-up connection—and the spectacular cascade of mistakes, miscommunications, and betrayals that would ultimately tear the two of them apart.