If you've read the books or watched the movies, no one has any knowledge of what had happened behind the closed doors of the Potter estate. During those years between the end of the Battle of Hogwarts to when it was Harry's second child's first year at Hogwarts School of Witchcraft and Wizardry, no one knew what the 'Savior of the Wizarding World' had to live through.
Harry and Cedric go back in time to the nineteen forties.