From the outside Elsa looks poised, regal and reserved, but in reality she lives in fear as she wrestles with a mighty secret: she was born with the power to create ice and snow. It's a beautiful ability, but also extremely dangerous. Haunted by the moment her magic nearly killed her younger sister Anna, Elsa has isolated herself, spending every waking minute trying to suppress her growing powers.
Her mounting emotions trigger the magic, accidentally setting off an eternal winter that she can't stop. She fears she's becoming a monster and that no one, not even her sister, can help her. This is a huge movie, seriously huge. You can tell the Disney animation studio really put mountains of effort and it shows they're firing from all cylinders now. Music and awesome sisterhood story separate this from many animation offerings of the past.