"It's just for a day, Viola. Please?"

Nobody understood Ellen. She was a sick girl, her family didn't care about her, and the only companions she had died.  One day, when a demon came along and offered her a wish, she couldn't refused. However, she had to kill her family as a sacrifice. Now, she became a witch, one that could use body-trading magic. One day, a girl comes along, her name was Viola.

What happened to Viola? Who knows.. She was never the same again.