Mary Katherine and her daughter, had just moved into her deceased husbands house on the Isle of Anglesey, Wales. Starting the first night and now the second night, she had been awakened clawing her way up through layers of sleep, driven by the anguish and terror in her daughter's screams. When she reached the bedroom door, blood greeted her again, Aline's fingers dripping red and sticky as she held her hands over the freshly cut runes in her chest.
Driven by anguish and terror for her daughter, Mary Katherine found herself staring at the clock in the waiting area of a local physician's office. The doctors professional concern turned to barely concealed terror as he informed her that the symbols are dangerous Druidic runes and told her to go see the local druid priest. Then he hastily bandaged the cuts and told her not come back again.
Before she can reach the druid priest, Mary Katherine sees evidence of an invisible entity attacking her daughter and abandons everything to rush to the druid priest. He discovers that Mary Katherine has druidic ancestry but her daughter, Aline, also has ancestry from the roman commander who decimated the druid community two thousand years earlier. The entity is the spirit of an ancient druid priest who escaped the slaughter and is set on revenge.
They trap the deranged spirit within a spiritual circle composed of Mary Katherine, Aline and himself. Then the circle is walked to the One Tree in the sacred oak Grove in preparation for entombing the evil spirit inside the tree. But he is too strong and would escape if the circle is broken. Only Aline has the power to directly attack the spirit, but she would have to sacrifice herself to do it.