Two of the Same Snowflake

Phoenix, Elsa, and Anna have grown up with the story of Jack Frost. Out of the three, Elsa seemed more intrigued. When disaster strikes, Jack becomes Elsa's only friend. She is forced to shut out her sister for the next thirteen years. Phoenix is sent away, for fear that her powers could destroy Arendelle. A wrong move and Elsa could die. It's up to Jack to keep Elsa alive and afloat. But what will happen to Phoenix and Anna?