Threshold of Madness

Av. A change of Fate. Tom Riddle, or Lord Voldemort, is given the job as Professor for Defense against the Dark arts. Dumbledore does it to keep an eye on the man he suspects is the new dark lord. How does this change the Marauders time at school with Professor Riddle being their main teacher and head of the Slytherin House? dark themes and ocs included.