Snowbird - Book One of The Aeternum Legacies

Snowbird Nixavem was a normal girl living in Vermont with her grandma. When masked men break into her house, Snowbird is given a silver key, and a book and is soon thrust into the world of Aeternum. She soon finds out she is not normal, and soon meets other children like her. They must stop a growing threat across the horizon, before it takes over their world, and themselves.