Okay I just finished your story and if I'm being honest, I liked it. I liked the plot a lot but I think you can (and should) expand a bit more. However, there were a few grammatical errors that I mentioned in the comments. I also think you definitely need to write it in a book/story format, for example, using quotation marks when someone talks instead of dashes and more dashes when the person talking switches to what they are thinking---
"Ugh what do you want Granger?" Draco scoffed.
"Nothing from an annoying ferret like you Malfoy," Hermione snapped back.---
That was just an example of the quotations marks thing. I hope I helped you and please don't think of this as hurtful, it is meant to be constructive (not even gonna say criticism bc it wasn't even considered), and I hope you continue writing bc siriusly, your story plot is amazing