The Chronicles of Starlyn (Calthoria Chronicles Book 1)

If Kheshlars are immortal, why is Starlyn's mother dying? With her mother's health failing, time is running out and so are the options for finding a cure.
Arria, Starlyn's sister, decides to act. Seeking a cure, Arria taps the forbidden power of dark magic.
When Starlyn learns of her sister's studies, she begs her to stop or risk becoming an outcast among the people. When Arria refuses, Starlyn must choose between her sister's freedom or her mother's life. The wrong choice could leave them both dead.