The Potions Master

SEQUEL to The Potions Journeyman. In his last year at Hogwarts, Harry decides he doesn't want to be an Auror anymore. He wants to be a Potions Master and will need Snape's supervision to become just that. He creates a potion that will allow him to speak with the dead, which doesn't bode well for Snape's internalized struggle. Mentor story. No slash.