Question

When Sirius is rescued by Harry and Hermione in Prisoner of Azkaban - where is he?

Answer 1

Answer: In Professor Flitwick's office on the seventh floor.

Explanation: The professor tells Harry and Hermione, "Now, pay attention. Sirius is locked in Professor Flitwick’s office on the seventh floor. Thirteenth window from the right of the West Tower. If all goes well, you will be able to save more than one innocent life tonight. But remember this, both of you: you must not be seen. Miss Granger, you know the law — you know what is at stake... You — must — not — be — seen."

Answer 2

In 'Harry Potter and the Prisoner of Azkaban', Sirius Black is rescued from the West Tower at Hogwarts where he awaits the Dementor's Kiss, and escapes with the help of Harry and Hermione on Buckbeak the hippogriff.

Step-by-step explanation:

When Sirius Black is rescued by Harry Potter and Hermione Granger in Harry Potter and the Prisoner of Azkaban, he is in the topmost tower at Hogwarts, known as the West Tower, where the room that holds the Flight of the Hippogriff is located. Sirius is locked in the room and awaiting the Dementor's Kiss, which Hermione and Harry prevent by using a time-turner to go back in time and save him. They rescue Sirius right after Buckbeak, the hippogriff, is saved, and they help Sirius escape on Buckbeak's back, fleeing into the night.