In the small village of Holm, Tora and her family live a safe, regular life despite an outside world awash in myth. Young Tora has heard many wondrous tales of the strange people and places beyond the walls of Holm. She always hoped that maybe, someday, she might have the opportunity to see it all for herself—but she never expected that hope to become a nightmare.

What begins as an act of neighborliness takes on an ominous tone when Tora and her mother visit Helga, a neighbor with a newborn. With gray skin and black eyes, the baby's horrid screams leave no doubt there is something wrong. Helga claims an evil creature took her baby, leaving a monster behind, and Tora soon learns Helga is right.

Tora's life takes a traumatic turn when the seasonal workers arrive for the summer. A young man with piercing blue eyes and mysterious tattoos is among them, and things will never be the same. In a valley long ago teeming with magic and trolls, Tora uncovers secrets she couldn't have imagined and sets off a series of disturbing events that alter her life forever.