Twilight's smart enough to have nothing to do with Rarity and her gang of delinquents. But as her world view is challenged and as Rarity takes interest in her, slowly Twilight finds herself getting closer to Rarity and becoming a delinquent herself.
Twilight Sparkle finds herself being led to question things she's never questioned and try things she'd never tried by Rarity. But slowly Twilight begins to feel like she's being corrupted, and begins to wonder if Rarity is a vampire.