( that was joke about this being a spoiler... I'm sure the tale is 'old as time' ) from how I remember it. Two children, boy girl -were they brother sister ? No... I think they were kids next-door. - the boy gets a splinter of a piece of glass in his eye and from that moment on his heart grows cold. He becomes mean and ignorant. The splinter came from the shattering of the mirror of evil somewhere in the sky above. On a wintery snowy night the beautifull but coldhearted snowqueen comes for the boy and takes him with her to the north or southpole ( who cares ). The little girl goes on a journey to save him.
On the other hand.., this could be a finding nemo in the snow with lots of pinguins and then I will hate Disney bigtime ;-)