Reflections of Arsulu

Everyone at the palace thinks Adella's new best friend, Arsulu, is wonderful. But Ariel has her doubts. Why is it, she wonders, that ever since Arsulu came to stay with them at the palace, strange and terrible things have been happening? A suspicious Ariel decides to spy on Arsulu to see if she's really to blame. That's when she learns the horrible truth about Arsulu. But how can Ariel convince her sisters that their dear, sweet guest is really a danger to them all?