How Voice Separates Children of Blood and Bone from Avatar: The Last Airbender

Picture a world where certain people are gifted with mastery of the elements. It is a land that lived in relative harmony until an ambitious king seized power by launching an unexpected attack. Our protagonist is a young adult, one of the last of her kind a people being driven to extinction in these turbulent times. She teams up with her brother and a third friend to try and restore balance but she must do so before the solstice. Also, she is being hunted by the son of said evil king, but ...