Letters and Panic

Harry Potter can't go back to the Burrow after the war. There is too many bad memories. Instead he vouches for staying at the Leaky Cauldron. When he receives an invitation to go back to Hogwarts he's hesitant at first, but he looks around Diagon Ally anyway. That when he meets an unsuspecting friend. The Golden Trio and The Silver Trio are the most powerful friends at Hogwarts.