No one knows what is behind the curtain, just like no one knows what is behind the bronze door. It is probably eternal life.
Sirius fell behind the curtain of the Department of Mysteries, only to find that there was only a bearded old wizard who liked to read fairy tales.
"Then take me back!" Sirius jumped up fiercely: "Please."
"So what can you give me?"
"Angthing." Sirius growled anxiously: "Anything is fine - as long as you send me back -"
The old man showed an unknown smile: "Speaking of which - your answer seems familiar."
Speaking of which, when I watched Harry Potter for the first time, I fell in love with the free and handsome Sirius. However, a few years later, as I watched Harry Potter over and over again, I fell in love with the silent and reserved professor.
"Severus, I've actually liked you since we were in school."
"It's a great honor."
"Don't you say something?"
"If you want to hear it - you should be glad that you didn't say it, otherwise I might use the Shenfeng Wuying to cut open your head to see if there is any corrosive potion poured into it -"
Protagonist: Professor Snape x Sirius
Supporting roles: Grindelwald x Dumbledore have been decided, others are yet to be decided...