This is a side story to Second Princess of the Night

Equestria lies in a state of peace, having returned to its comforts after the string of recent incidents, each of them capable of vast destruction in their own right. But the series of threatening events has yet to end, and an evil from the past re-emerges with the darkness it had once walked. With its return, Princess Twilight Sparkle vanishes, a sister perishes, and the traditions of old bloodlines that had been kept secret now reveal themselves.

It is said that a hero is destined to do great deeds, and that through careful guidance and growth, they will topple any foe or evil that stands in their way. The young are often trusted as the bearers of these hopes and ideals, to be a new generation to fight the sins of the past. Yet despite the claims of heritage, or the careful guidance of wise teachers, even the most promising of heroes will still perish. Regardless of whatever books you may have read that said the hopes of the future lie in the youths whose unknown destinies have been thrust into their lives, one simple fact will remain. The good die young.