Since we only know about the 'jeremy zoe secret story', it's difficult to say precisely who they are. They could be individuals in a small town where everyone knows each other and this secret story is something that only a few are privy to. They might be artists who have a secret creative process that they don't want others to know about. Or perhaps they are athletes who had a unique training experience that they are keeping under wraps.
Marinette is the main female protagonist in Miraculous Ladybug. She's a young girl with a kind heart and a secret identity as a superhero. As for Camemburt, it's likely a character made up for this particular fanfic idea. Maybe the author wanted to create a new love interest for Marinette, so they came up with Camemburt. But again, this is just speculation without actually reading the story.
Zoe could be a new student at Hogwarts who gets into trouble. Maybe she's a first - year who wandered into the Forbidden Forest by accident and Harry has to save her from the dangerous creatures there.
Percy could be a brave and adventurous character, perhaps with some special abilities like being able to control water or having enhanced strength. Zoe might be a smart and resourceful female character, maybe with skills in tracking or archery. They could be from a fictional world full of magic and mythical creatures.
Marinette could use her wits. If she's tied up, she might be able to find a sharp object nearby to cut the ropes. For example, if she's in a room with some old furniture, there could be a nail or a broken piece of wood that she can use.
Another reaction could be that Marinette pretends to cooperate with Adrien at first. By doing this, she can buy time and look for an opportunity to escape or get help. She might act as if she is okay with what is happening while secretly planning her next move, like leaving a clue for someone to find her or finding a way to disable Adrien temporarily.
She might befriend Iron Man first. Since he's into technology and Marinette is quite creative when it comes to making things. They could bond over creating new gadgets or improving existing ones.
Marinette can react by standing up for herself. She might confront Chloe directly and tell her that her actions are wrong. This shows Marinette's strong character.