The way I see it theres 3 options:
1: Daily life stuff. Nuff said. Think like Puchimas without the Puchi-idols
2: Do some kind of fantasy plot in the future or feudal japan or something. Include a twist to show it was all a dream or a game or something similiar Don't read this if you aren't Liza94!
3:Lewd things .
EDIT: I guess it depends on your tastes. Do you like horror? Action? Comedy? Romance? Are you good at hinting at twists later or giving vague hints? Help up help you. Give us some ideas on what your good at!
Well, start with the idea that this is a new trio that is being produced. Think about the characters and how their personalities might clash with each other as they are on the road to top idol. Try giving them a rival or something that they have to rise up against.
Thank you both for your ideas!
I don't know what style I'm good at yet. And there are some problems:
1. I can't stand the "P's unit loses to RK" idea of im@s2, but I can't make up anything better!
2. When I think of Mami, only one sentence comes to mind: "Mami misses Ami very much because Ami is in RK.". I can say much more about Chihaya and Hibiki!
3. Hibiki's way of speaking.