Eighteen-year-old Calla Benson is like any other normal teenage girl. She has a secret crush on her best friend, likes music and movies, works hard to make good grades, and does her best to stay out of trouble. But once in a blue moon, Calla is anything but normal. There's a predatory animal lurking inside her, just waiting to rampage through the forest once a year.

One fateful night, Calla comes across something she's never seen before—someone like her. After a tense meeting in the forest, Calla dives headlong into a fantastical land she never knew existed. She learns things are not always what they seem, and she is farther from normal than she ever imagined.

With the help of her best friends, a pair of quirky brothers, and a family she never knew she had, Calla embarks on a mission to save her people from a treacherous queen. With wolves, witches, deathly secrets, and mysterious lands (and a few confusing boys), Calla's life is flipped upside down. It's the stuff fairy tales are made of... because being a teenager wasn't already difficult enough.