The central theme I'm going for in The School is "trust and reliance on others." Ariel's parents are rarely around, and while she has friends, she depends on herself rather than others - to a fault. I'm going to introduce dynamics between Gwen and Jeff, a pair of fostered siblings, and their reliance on each other, and a few other pairs of characters, but the main focus is the relationship between Ariel and Jesse. Ariel is a flautist who could probably make it in the world of music - Jesse, due to events in her childhood, has been saddled with severe epilepsy. While Ariel considers Jesse her "best friend," in reality she doesn't treat her so much as a friend as like a child, fretting about her and trying to take care of her. This conflict begins even before they're kidnapped, with Ariel considering applying to or attending a music conservatory, but leaning in the direction of giving up those dreams to stay with Jesse, who "needs her." Jesse doesn't really appreciate the excessive care, but hasn't yet gotten up the courage to tell her friend to back off. Throw psychic powers and the kidnapping of around a hundred kids into the mix, and watch the explosions.
Also printing out a copy of Familiar so I can outline it. Ah well. Work!