The Bone Shard Daughter takes place in a world of moving islands ruled by an emperor with an army of animal constructs. It follows four storylines: Lin, Jovis, Phalue and Ramani, and Sand. Lin and Jovis were my favorite points of view. 
Lin is the emperor's daughter. She lost her memories five years ago and is trying to win back her father's love. I enjoyed her character arc and her relationship with her foster brother Bayan. I thought the bone shard magic was very interesting, especially the moral struggles that come along with it and how it echoes the moral issues of empire. 
Jovis, and his lovable animal companion Mephi, are searching for Jovis' lost wife. I loved Jovis as a character, his inner voice was unique and I enjoyed how he struggled with his morals and his goals when they conflicted. Mephi is my favorite character in this book. 
Phalue and Ramani felt like a typical romantic rebellion against the empire story. 
Sand's POV was interesting, and I'm looking forward to seeing what she'll do in later books.