It is 1900, 7 years after you graduated Hogwarts. You walk in a new potion shop / apothecary in Diagon Alley. The place seems to be quite grand, specialising on custom potions and new versions of the old ones. Browsing among the stands and shelves you meet the owner and recognize the man instantly - who else but the Hogwarts prodigy with potions, Garreth Weasley himself.