Sparkchaser, Luna's protege, is a gifted student, but an absolute failure at social interaction. With Equestria is threatened with open war against a dark, ever-changing brood of shapeshifters, can a young stallion afford personal relationships, or will he leave his potential friends by the wayside as he pursues a foe as relentless and unpredictable as change itself?

Mature because I know what's coming (what with sixty chapters already written, though being edited. Compulsively.)
[Dark] tag because war.