One possible plot could be that Harry discovers some long - lost secrets about Tom Riddle's early days at school. Maybe he stumbles upon a hidden diary that reveals Riddle's true motives even before he became Voldemort. This could lead to Harry trying to prevent some of the dark magic that Riddle was starting to dabble in from ever happening.
The plot might involve time - travel. Harry could be sent back in time to attend school with Tom Riddle. He then tries to influence Riddle in a positive way. He might introduce him to different friends or try to get him interested in more positive forms of magic. But things could go wrong as Riddle's pride and his already - forming dark desires might resist Harry's attempts at change.
Tom Riddle himself could be the main antagonist. Even in his school days, he was showing signs of his future as Voldemort. His dark thoughts and actions towards other students or his exploration of dark magic could put him in direct opposition to Harry.
One possible plot could be that Harry, using his knowledge of love and friendship, tries to teach Tom about the power of positive emotions. He might show Tom how his own journey was shaped by the love of his friends and family, in contrast to Tom's more solitary and power - hungry path. Maybe Harry takes Tom to Hogwarts in a time - travel like scenario and shows him the true meaning of the houses, not just the pursuit of power within Slytherin.
One possibility is that Harry, having seen the dark path Tom Riddle took, decides to take him in early. He might teach Tom about love and friendship, things he lacked growing up. Harry could introduce Tom to the wizarding world in a more positive light, showing him the joys of Hogwarts and the value of good relationships, thus preventing him from turning into Voldemort.
One possible plot twist could be that Tom Riddle discovers Harry has a hidden power that he didn't expect. Maybe Harry has the ability to resist Riddle's mind - control spells in a unique way. This could lead to a battle of wills between them where Harry tries to outwit Riddle while being held captive.
One possibility could be a story of internal conflict for Harry. He might struggle with the dark heritage from Tom Riddle while trying to uphold the values of the wizarding world he has grown to love. He could constantly battle his own darker instincts that come from being Voldemort's (Tom Riddle) son. For example, he might have an in - built talent for Parseltongue that he has to learn to control and use for good instead of evil.
Well, one possibility is that they try to change Tom's fate. Since they know the dark path he'll take in the future, they might use their knowledge of magic and friendship to guide him towards the light. Maybe they introduce him to a different kind of magic, one that focuses on helping others rather than power for its own sake.
One possible plot twist could be that Tom Riddle kidnaps Harry not for the typical reasons like revenge or to gain power over the wizarding world. Maybe he discovers that Harry has some hidden knowledge about a long - lost magic that he wants for himself. Another twist could be that while kidnapped, Harry manages to find a way to get into Tom Riddle's mind and discovers his deepest fears, which he then uses to his advantage to try and escape. It could also be that there are other dark forces at play that Tom Riddle is actually trying to protect Harry from, in his own twisted way, by taking him away from the wizarding world for a while.
One possible plot could be Harry struggling to adapt to the strict discipline of military school at first. He might have conflicts with the drill sergeants who are tough on him. But as time goes by, he discovers his own inner strength and leadership skills, and eventually earns the respect of his peers and instructors.
Well, it could be about Death taking on a form that can attend Hogwarts with Harry. Maybe it's there to protect him in a more direct way than the usual magical means. It might interact with Harry's friends, causing some confusion and also some revelations about the nature of life and death in the wizarding world.
Maybe Harry could struggle with the language at first. He might make new friends who introduce him to French wizarding traditions. And he could have adventures in the unique French school setting.