"In new situations, all the trickiest rules are the ones nobody bothers to explain to you. (And the ones you can't Google.)" 
 Cath is a major fan of Simon Snow (think Harry Potter), and a writer of very popular fanfiction about the series' characters. She is also a college freshman with social anxiety, left to deal with the newness of college (with all of its dorms, classes, and boys) without the help of her more social twin sister, Wren. 
 I found Cath to be very relatable, and so many of her thoughts and actions while navigating new social situations really resonated with me. I was also pleasantly surprised by some of the story's unpredictability, that foreshadowed events (view spoiler)[definitive/described sex with Levi? fame and fortune from Carry On? Nick snapping and coming to murder her in the dorm? (hide spoiler)] did not occur. 
 That said, I was not interested enough in the Simon/Baz parts to read a whole book about them. I started reading Carry On a while back and didn't get far; the additional information about the premise I've gathered from this book didn't improve matters (view spoiler)[What if Harry Potter and Draco Malfoy were even more good and more evil (respectively)? and they had to be roommates? And lab partners? And Draco was a vampire? And Harry and Draco were in love? Eh. (hide spoiler)]. I gave it another shot, but it's now moving to the abandoned shelf.