Billie didn't plan on noticing her best friend's friend. But then Athena walked in-older than her, hot, and magnetic-and suddenly, pretending not to care is way harder than it should be. Because it's one thing to deal with late-night music sessions, inside jokes, and the usual chaos of friendship. It's another thing entirely when the new variable in the equation is someone who makes you rethink all your rules. And Billie's starting to realize: some problems are way too tempting not to have.