Harry had just gone to Diagon Alley and Hagrid has placed him on the train back to his relatives, but Harry didn't want to go home, he never wanted to see the Dursley's again, so he got off the train and returned to Gringotts where his future path has changed.
Summary: What if Harry managed to slip away from Hagrid as he was staying in the Leaky Cauldron the first night of his visit to Diagon Ally in his first year, giving him an unbiased view of the magical world.