After Fifth-year, it was clear that Sebastian wasn't the same.
You had hoped that it would have been something easy to figure out—and considering everything that happened, between his sister's curse and almost losing you to Ancient Magic, you just wished it would fix itself.
But after Sebastian spent most of sixth-year away from Hogwarts, due to the death of his Uncle—you barely got to see him, despite your relationship becoming more than friends and when the letters stopped, you knew something was wrong.
Now it's your last year—the finale to all the drama and all you wished to do was to make things right with Sebastian, but nothing could have prepared you for what was to come. Sebastian had more than just changed, it seemed that he had forgotten you, forgotten everything that happened over the last few years and no one would tell you why. It drove you insane, the idea that everything he had been through—you both had been through was gone, just like that and for some reason, it was as if everyone just hoped you'd give up.
But that wasn't you and you knew if the roles were reversed—Sebastian would do everything in his power to get you back and so, that is what you planned to do.
Help Sebastian remember his past, remember you—no matter how painful.