They have already passed on the third course Hogwarts . As in previous years, Harry was forced to spend summer vacation at their guardians-family of the Dursleys. They always do not particularly get along, but this time it has gone much further, and in the heat of anger hero applied magic that strictly prohibited outside the school. After Harry leaves home and soon meets with Ron and Hermione. But friends do not enjoy meetings, because they report that escaped from prison henchman and servant of Voldemort-Voldemort Sirius Black. Black is the Godfather, Harry, and once upon a time he was a good friend of his parents. But after the events, when they died, he was a traitor and imprisoned in Boggart would take. But now, when Sirius free, all seriously concerned for Harry's life.