High school senior Delia Bridges has the most amazing mom and sister, a killer GPA--and periods that are so painful they make her scream, pass out, and throw up. Though she doesn't know it yet, Delia has endometriosis, an affliction plaguing millions of people that is notoriously difficult to diagnose.

Pain makes everything harder, but Delia is just one semester away from graduating from Stockwood Prep and pursuing her dream of becoming the kind of doctor she's never had: one who takes her symptoms seriously. But when she breaks a rule for the first time ever and is caught using marijuana at school to manage her pain, Delia is expelled.

Her expulsion jeopardizes her college acceptance, her planned mentorship, and everything she had carefully planned for years. Without her academic success and no closer to a diagnosis, is Delia anything more than her period?