The ancient supernatural entity Cailleach's confrontation with the modern world as manifested through the blood ritual and stone circle prophecy

Romana detects an arcane disturbance at the stone circle and alerts the Doctor, who quickly deduces that a ritual is imminent or already underway. He asks Emilia for her research …

The Cailleach completes a forbidden blood ritual at the stone hollow, pouring the offering while chanting to summon the Ogri. As the stone glows with supernatural energy, the Cailleach demands …