One Misfired Spell Later

Harry is hit by a misfired undoing spell in third year and starts to remember things causing him to flee together with Hermione and a few others, including a godfather he didn't know he had. For Wizarding Britain and Dumbledore in particular old oaths and secrets are now brought to light. Dumbledore bashing, AU. Story ends at the end of the year, continued in a sequel (not yet up)