One interesting plot could be Valerie finding out about Danny's ghost powers in a very public and dangerous situation. Maybe they are in the middle of a fight with a powerful ghost and Danny has no choice but to reveal himself to save Valerie. Another plot could be Valerie slowly suspecting Danny over time as she notices little things about his behavior that seem strange in relation to the ghost attacks. For example, he always seems to disappear right before a ghost shows up.
Well, in some fanfictions, Valerie finds out about Danny through his friends. His friends might accidentally let it slip that Danny is also a ghost. This leads to Valerie having a huge internal conflict. On one hand, she has been hunting ghosts, but on the other hand, Danny is also her friend. She then has to decide whether to keep his secret or expose him, and this decision-making process can be full of drama and emotion.
Well, obviously Danny and Valerie are the main ones. Danny, with his dual identity as a high school student and a ghost - fighting superhero. Valerie, the ghost hunter who is always on the lookout for any spectral activity. Tucker and Sam, Danny's best friends, often play important roles too. They might be the ones trying to protect Danny's secret from Valerie or they could accidentally be the cause of Valerie finding out.
One interesting storyline could be Valerie discovers Danny's secret identity in a really unexpected way, like during a ghost attack where she's about to capture him but then realizes who he really is. It adds a whole new layer of drama to their relationship.
One idea could be a story where Danny and Valerie have to team up to fight a new, powerful ghost that neither can defeat alone. They start off distrusting each other but as they face challenges, they learn to work together and gradually develop feelings for each other.
In this fanfiction, Nathan could be a new student in town who has a strange connection to the Ghost Zone. Valerie initially suspects him of being a ghost or working with them. But as she investigates, she realizes that he is actually trying to close a dangerous portal to the Ghost Zone that was accidentally opened by one of his experiments. Valerie then decides to help him, and during the process, they face many challenges and dangerous ghosts. Through this adventure, they form a deep bond and become an important part of each other's lives in the Danny Phantom universe.
One possible plot could be that Danny is kidnapped by a new ghost enemy who wants to use his powers for their own evil deeds. Maybe this enemy plans to drain Danny's ghostly energy to become more powerful. Another plot could involve Danny being kidnapped by a group of his human enemies who have finally discovered his secret identity and want to experiment on him. Or perhaps a time - traveling villain kidnaps Danny to prevent him from ever becoming a hero in the future.
In a Danny Phantom fanfiction involving Valerie and Nathan, they could become allies in the fight against ghosts. Maybe Nathan discovers Valerie's secret identity and offers his technological expertise to help her upgrade her ghost - hunting gear. This would make them a formidable team, taking on powerful ghosts that Danny might have trouble with on his own.
One possible plot could be that Danny's sneeze accidentally activates a new ghost power. For example, every time he sneezes, he temporarily gains the ability to phase through different dimensions. This could lead to all sorts of adventures as he tries to control this new and unexpected power while also dealing with his regular ghost - fighting duties.
Maybe Danny and a ghost enemy are stuck together due to some strange ghostly spell. This forces them to understand each other better as they try to break the spell. As they are stuck, they start to see the other's point of view, which could lead to an unexpected friendship or at least a truce.
One possible plot could be that the evil Danny Phantom tries to manipulate Sam into helping him take over the Ghost Zone. He might use his powers to deceive her at first, but Sam gradually realizes his true intentions and has to find a way to stop him.
Well, one interesting plot could be Danny finally revealing his secret to his best friend Tucker in a really dramatic way. Maybe it's during a ghost attack and he has no other choice but to show his powers to save Tucker. Another plot might involve Danny's parents finding out his secret through some accidental discovery in their own ghost - hunting experiments.