Harry Potter and the Mysterious Traveler

The full name of the book is "The Adventures of the Azkaban Sweeper and His Gryffindor Cleaner Niece, the Slytherin Goose Niece, and the Hufflepuff Hufflepuff Niece, plus the Ravenclaw Preparatory Headmaster's Niece." Because the name was too long, I wrote a short name, and the plot begins with the third part of Harry Potter, and Hannah, who refuses to fight, starts with me.