The main characters are Harry Potter, Hermione, and the Weasleys. Harry is having dreams all of the time about a long dark hall with a locked door at the end of it. He is also having a stronger connection with Voldemort and is trying to find out what he is doing and how to stop him. Ron and Hermione help Harry to solve this mystery.
Middle of Book
Harry Potter has made a Defence Against the Dark Arts group for when they might get confronted with one of Voldemort's followers. He is trying to find out what is past the locked door and he is taking Occlumency lessons to try and close out his mide from Voldemort.
End of book
Im on page 648 and there is a total of 870 pages in the book. The part im at right now is Harry is looking into Professor Snape's memories and he is looking at a young teenage Snape while Snape is gone doing something.