By Sun and Saltwater — Kate Avery Ellison

Aemi has a new life beneath the sea in the world of Itlantis, but all is hardly idyllic -- her assimilation into Itlantean society is fraught with accusations and rumors, those closest to her are keeping deadly secrets, and most frightening of all, someone is trying to kill her. Desperate for answers, Aemi and her friends set off to find answers in Arctus, the Ice City, but they might uncover more than they bargained for in the process.