The Renegades of Pern (Dragonriders of Pern Series #10)

Behold Acorna, the Unicorn Girl. Discovered as an infant and adopted by three gruff asteroid miners, she has now grown into a beautiful young woman with delicate ivory fur and silken skin, the tiny horn on her forehead all but hidden by her silvery locks. Acorna is known as Lukia of the Light by the grateful children she rescued from brutal slavery in the mines of Kezdet. She is helping them recover, and enjoying life with her guardian "uncles," when she receives a mysterious and disturbing mess…