Best Friends With A Death Eater

Originally published on my old account, but I got locked out of it, so please read this here.
Parvati Patil is a seventh year in Hogwarts, and her and her friends are proud members of Dumbledore's Army.
Together they fight against the Carrows, and the other Death Eaters.
What happens when one day she finds out that her best friend might not be as loyal to the light side as she thought? Will the friendship prevail? Will Parvati go to the Dark side, or will she betray her friend and reveal her as a traitor?