The two main characters are Brad, the good looking guy who moves to Winfield, and Tracy, a "normal teen-age girl, is flattered by his attention, but knows he is not what he seems."
Who are the "good" guys and the "bad" guys is a harder question to answer. Here is an excerpt about the novel from the pages here at eNotes which explains why. You can find out more about the characters, themes, and other literary elements by visiting the link below.
"The reader is unsure which characters to trust; personalities which should be obviously "bad" or "good" are not. Duncan accomplishes this confusion with skillfully plotted clues which do not fit neatly together. Even the window through which the heroine gazes confuses her due to an irregularity in the glass; hence the book's title. This "twisted" point of view becomes the major theme of the story as the reader follows the heroine in attempting to make sense of confusing bits of information."