The Oath (Dramione)

Eight years after the war, Dolores Umbridge becomes the Minister for Magic. She's behind a new wave of anti-Muggle-born propaganda that slowly worsens until it results in monthly examinations called the Mandatory Monthly Magical Stability Test for Muggle-borns (MMMSTM).

In the fourth month, Hermione loses her ability to perform magic. She's taken away to an "underground clinic" supposedly meant to help her regain her powers, only to discover she has actually been imprisoned for life in a dungeon beneath the Ministry. With no friends left, she would die there without anyone noticing.

Or so she thought.

Because one day, she wakes in the new Malfoy Manor with a gold choker clasped around her neck-one that burns her skin every time she tries to escape.

So at least someone would notice, even if it meant that someone might be the one to end her.