After Elsa melted Arrendale, Anna and Kristoff got married. They had a child, a little boy named Congelado, who was quickly nicknamed Connor.
Shortly after Connor was born, Elsa met a boy. A boy named Jack. Jack didn't have ice powers like Elsa, but he helped her with them. They fell in love, and when Connor turned two, they were married. Now it was their turn to have a child, this time two baby girls whom they named Ellie and Ella.
Ellie was a sweet baby, always gentle, always quiet. She'd coo and giggle, never cried.
Ella was sweet too, and cute beyond it's measures. She was a rebellious baby, the exact opposite of her sister. She'd cry, and scream, but her parents loved both twins equally.
Ella grew and grew, but on her 3rd birthday, she disappeared. No one could find her. Everyone assumed her dead.
Ellie grew up as a normal child, and she was never told of her sister. On her 10th birthday, everything changed.
She had the curse.