It is also a Crossover with Chronicles of Narnia

Sunset Shimmer is a monster. After the Fall Formal, everyone in the CHS knows this.
But it was not always so. Long before, Sunset Shimmer was a student of Celestia, a magical prodigy and a nice little filly. But the friendship lessons of the kind Princess of the Sun were not the only ones she has learned.

This is story is a tale of one of such lessons - a story of her furthest adventure, her first war and most importantly of all it is a story of her first friend.

P.S.
My greatest gratitude goes to Orbittal Kettle and the true author of the "Sparks on the Wind" for being patient pre-readers and editors without equal. Thank you guys.