Polly loves words, writing, and telling stories, so when she finds a fancy book on her doorstep labeled "Special Delivery from the Writing and Spelling Department for Polly Diamond" she is thrilled; and when she finds that anything she writes in it actually happens she is really excited--but Polly soon realizes that she has to be very careful what she writes because that kind of power can be dangerous.

Today is the school book fair, which is very exciting for Polly Diamond, who loves books and writing, and who possesses a magic book which turns anything she writes into reality--but she also has to be careful because sometimes her book, Spell, does not quite understand a word and misinterpretations can be catastrophic.