Gravemaidens by Kelly Coon 

In the walled city-state of Alu, Kammani wants nothing more than to become the accomplished healer her father used to be before her family was cast out of their privileged life in shame. When Alu’s ruler falls deathly ill, Kammani’s beautiful little sister, Nanaea, is chosen as one of three sacred maidens to join him in the afterlife. It’s an honour. A tradition. And Nanaea believes it is her chance to live an even grander life than the one that was stolen from her. But Kammani sees the selection for what it really is-a death sentence… Read more.