Boys, Girls, and Other Hazardous Materials by Rosalind Wiseman (January 12th 2010--Putnam)
"Charlie Healey thinks Harmony Falls is the beginning of a whole new life. Middle School was brutal. Mean girls were all around her. But High School’s going to be Charlie’s big chance to start over and stay out of drama, except that on her first day who does she run into? None other than Will, her ex-best friend, who had moved away. Now he’s back, looking a lot cuter and hanging out with a questionable crew. But Charlie doesn’t understand just how questionable until an innocent delivery guy falls victim to a near-deadly hazing prank.
All Charlie wanted to do was have a drama-free freshman year, but now she must decide whether to turn in her very best friend, who just told her he loves her, or live with the guilt of knowing what he did."