Fallon is a fixer. From planning prom to organizing her college applications, she’s got it all figured out…except for when her younger sister comes to her with very basic questions about sex. Shocked that she knows so little—and her fellow classmates even less—Fallon decides some practical education is in order. And Fallon isn’t above practicing a little civil disobedience by creating a secret underground off-campus group.

Shelby is a fighter. Having her nose broken is nothing new in her semiprofessional career…but this time it’s her boyfriend who threw the punch. Now her phone is blowing up with texts from a new guy who tells her she’s perfect, she’s special, she’s everything he’s ever wanted…except for a few small details. Shelby’s happy to adjust for him, because isn’t that what a healthy relationship is about?

Jobie is a failure. She doesn’t have enough followers and her posts never go viral, no matter how hard she crushes challenges and applies exactly the right filter. But a friendly DM from a good girl just like her points her in the direction of a whole new audience of admirers. Guys who just want to talk. Guys who give her the attention she’s always wanted.

The lives of all three girls intersect in Fallon’s secret class, rumors of which have parents up in arms. Fallon needs to keep herself anonymous, Shelby needs to keep her new boyfriend happy, and Jobie needs to keep her followers…who keep asking for more. Each girl finds herself trapped in an inescapable situation—that will leave one of them dead.