Pepper Carter has felt unloved for all of her life. After a particularly bad fight with her abusive mother she runs off into the street and falls down an open manhole landing into the arms of the most gorgeous boy she's ever seen. Soon she's taken into the folds of a gang of misfit kids just trying to survive in the massive subterranean city of Underground. She has finally found a place where she belongs. Only problem, they all think she... is a he.