Sapphire City — Amy Richie

Strange things happen on Nortica; people disappear and voices call from the ocean. For Stella Shaw, things are about to get even more weird. Welcome to Nortica. Population: ten. After her latest run-in with the police, Stella's mom takes her back to her childhood home, the island Nortica. But they find it much different than the stories Mom told. Most of the people have disappeared and the ones left are really weird. When her mom turns out to be the next victim of the island, Stella is forced into a dangerous race to find her while learning the secrets that the ocean holds.