Judy Sheehan's debut young-adult novel is a terrifically fun read that also tackles some of life's-and the afterlife's-big questions.Last night Sarah was a bridesmaid, dressed in a hideous peach gown. Today she wakes up dead at the Mall of America. This is where the universe sends teenagers who were murdered. In fact, most malls are haunted. The living don't notice it, what with all the bright lights, sales, and free samples. The dead just pass through...