Sombra isn't just transferring to a new school; he is starting a whole new life. Sombra is the kindest, most respectful person anyone would hope to meet, who carries with him an aura of incredible malevolence.
Is Sombra truly evil? The only way for Sunset Shimmer to find out is to befriend the tyrants human counterpart, to dispel his dark magic, or destroy him utterly.
But Sombra is not the only danger present in Canterlot High. Sunset Shimmer and Adagio Dazzle are every bit as unusual as Sombra, and each possess powerful magic capable of remaking the world.