The Magnum Opus

Gringotts and Hogwarts have failed to hide it, so as a last resort Dumbledore turns to the only other place that can rival them. Nurmengard, built and warded by the two brightest minds of the age is the only place that could hide the Philosopher's Stone. But hiding it from one dark lord puts it within easy reach of another. Idea credit to Darth Krande, written with permission.