He Stuns You By Degrees

When Hermione Granger is chosen to succeed Minerva McGonagall as Professor of Transfiguration at Hogwarts, she is delighted. That is, until she meets her newest coworker. Former Death Eater Draco Malfoy is just trying to turn his life around doing what he loves, but that becomes distinctly more difficult when he encounters his past at every turn. When you combine Hermione Granger, Draco Malfoy, a whole lot of teenagers and a little bit of magic, what do you get? Well, this.

(published on AO3 under the same name)