Don't Panic

Four alicorns to unite the races and protect the kingdom of Equestria. That's how the old legend goes. Years after its creation two sisters are born, one an alicorn and the other a unicorn. One became angry at the other's actions, and ended up sealing the fate for the two with a spell that had unforeseen consequences...

Years later when Celestia is a name all but forgotten to the flames of the sun, Luna is on a desperate hunt for any signs of her sister. Cadence and Flurry Heart have been born while Luna still believes Celestia is the fourth alicorn of the age old story, unbeknownst to her the dark secrets that lie with her sister's wings, and a very important mare hidden in the streets of Canterlot... But nobody's panicking. Right?