@mckapo
Yes, yes, I know this is a rather cliched idea, overly done and whatnot, but I love me some gifted high school stories for some reason.
Anyway, the initial idea is that two sisters (or brother/sister) enroll into a school for gifted students to find clues about their missing father.
What could be a good conflict to add into this?
I have one that someone gave to me: [s/n] changed to brother and sister
***I think if your sisters' father was a supervillain it would make for a super interesting plot. You could start by throwing in a few red herrings - the sisters could suspect that a minor hero was their father, then eventually start to think that the supervillain's arch-nemesis was their father, and finally come to the terrifying conclusion that the supervillain was their dad. Then you could tie the second sister's superpower in with the villain's. For example, if he can control fire, have her control either something similar or opposite - not something totally unrelated.
The conflict between the sisters could evolve as the second sister's genetic tendency towards evil begins to blossom and the other sister starts to fight with her over certain choices she's making or ways that she handles things. Then you could have the climax of the story basically be the second sister's choice between good and evil.***
Also, one sibling has vibration manipulation and still thinking on the power for the other sibling