Sunbeam Shimmer stood in front of the portal at Canterlot High. She sighed, watching the sun set. Her young daughter, about less than a month old, was curled up in the blanket. She placed a card on her chest, which read, Sunset Shimmer, before shoving the young infant into the portal.
Over on the other side, was a princess, Princess Celestia. When she saw the baby unicorn foal, she was astonished.
Celestia resolved to take the child as her own, and raise her.