Harry Potter and the Goblet of Fire
Harry Potter and the Goblet of Fire is the fourth novel in the Harry Potter series by J.K. Rowling. Harry is underage but gets entered into a dangerous wizard tournament that is only for adults 17 and over. Harry does not know who entered his name but he did not. Eventually he discovers that it is one of his teachers, Mad-Eye Moody, who is actually Barty Crouch, Jr., a dark wizard and supporter of Voldemort, disguising himself by use of a potion and keeping the real Mad-Eye prisoner. Harry is rescued, but not before one of Voldemort's supporters manages to take Harry's blood to resurrect the Dark Lord.