Emma and the Box of Wonder - Tales of Widowswood, #6

Emma planned to have a nice fun day playing with her sister and friend... not going halfway across the world. For most of her ten years, Emma always felt apart from other children in the village, always trying to be responsible, helpful, and mature. When Ambril Starling, the closest person she has to a real friend, invites her over to play, Emma is excited at the chance to simply have fun for a while. Alas, Ambril's family is incredibly wealthy, leading to a rather inconveniently timed abduction attempt interrupting their play date.
While hiding from thieves, the girls stumble across an enchanted jewelry box that accidentally saves them from being kidnapped-only to put them in much, much bigger trouble. Trouble that might even kill them.