The Cursed Love Story of a Slytherin and a Gryffindor

What happens when Harmony Euphemia Potter meets Regulus Arcturus Black? Her older brother and his best friend always told her that Regulus Arcturus Black was an evil bad person. But what happens when she transfers from Beauxbatons to Hogwarts and finally meets Regulus on the train after she couldn't find her brother? What happens when she doesn't see him as an evil bad person but a hot, kind-hearted, book-loving boy instead?
Face Claim:
Harmony--Katherine McNamara
Regulus--Timothée Chalamet