Assistant Professor Sherlock teaches seventh year John in potions Johnlock fluff :)

"...I wish we could turn back time, to the good old days..." When Sherlock Holmes and his cousin Henry (Short for Henrietta) meet John Watson on the Hogwarts Express, they don't know the sheer amount of hidden secrets that will come to light. But not for a single moment do any of them wish they had never met. Especially when Sherlock and John develop feelings for each other. Even though their lives are soon threatened by a monster they used to call a friend. It's only their fifth year at Hogwarts, but it will change their lives in an irreversible way. A potterlock story, with Johnlock (obviously), and Percy Jackson references. (Takes place during Prisoner of Azkaban)