Prince Crystal Sword knew that his mother Cadance would out live both he and his father Shining. However, after saving a pony from an attacker, he unlocks the alicorn gene with him, taking on the role of a guardian of Equestrian.
Now Crystal must endure as his he and his mother remain young. Meanwhile his father Shining continues to age, a fact with causes him great turmoil. And when the Empire is thrown into a war with the changelings, the young prince and his mortal father will fight for each others survival in the frozen tundra of the north. If Shining Armor is to die, Crystal Sword is bent on makeing sure changelings play no role in his fathers inevitable death.
This story is apart of a split timeline of the My Mortal Big Brother saga, but is also a prequel of sorts. It takes place in a universe where Shining Armor never had the nightmare that scared him into seeking immortality.