Harry Potter must not go back to Hogwarts.
“Harry Potter must stay where he is safe. He is too great, too good, to lose. If Harry Potter goes back to Hogwarts, he will be in mortal danger.”
“Why?” said Harry in surprise.
“There is a plot, Harry Potter. A plot to make most terrible things happen at Hogwarts School of Witchcraft and Wizardry this year.

Author: J.K. Rowling