What if Harry didn't handle the events following the Triwizard Tournament as well as he did in the books or as calmly? What would happen if he could no longer keep the facade of bravery and stoicism as he did following the confession by Barty Crouch and broke down when he thought he was alone and Snape came across him in this state?
Can be played with as you like and be as a one-shot or multi-chapter story. How things play out is up to you but the story must fit the parameters of the definition and come into play. Can take place after incident in Hospital Wing, Croch's confession, PostGOF or PreOOTP