Tara just wants to be treated like any other girl at Ainsley Academy. That is, judged on her merits--not on her transness. But there's no road map for being the first trans girl at an all-girls school. And when she tries to join the Sibyls, an old-fashioned Ainsley sisterhood complete with code names and special privileges, she's thrust into the center of a larger argument about what girlhood means and whether the club should exist at all.