Ken Follett's Journey Into the Dark Ages

Arthur, a socially malformed outcast, has secretly lived inside the walls of the local high school since his Freshman year spending his days spying and obsessing over his former classmates…and one girl in particular – Wendy. When Wendy gets her heartbroken by the high school hotshot, Arthur sees his chance to swoop in and enact revenge on his enemies. Erica and Brett. (Holiday Theme: First day of School)