Harry potter and the prisoner of azkaban
Protagonist - Harry potter, Hermione granger, Ronald weasley, Remus john lupin
Antagonist - Sirius black, Peter pettigrew
Short summary - Sirius black, notoroius mass murderer, is on the loose. Harry found the Maurauders Map. On it he finds a dot whch he thought to be dead, Peter pettigerw. Will young Harry be able to discover the truth behind the mystery and also about his DADA teacher, Remus John Lupin?
I recommend this book as this one should think before he speaks.