My memory speaks of loving you.
Prerequisite settings:
Sirius Black is not dead (I know this is very unscientific). It was written after the war. Everything is the memory of the heroine, a short story.
There are dual endings. If you don't like BE, you can skip directly and jump to HE.
You can substitute it into the song "While Your Lips Are Still Red" by yourself. The last chapter bgm: Luv Letter
Mission: Eternal love
I read it again and was very impressed.