With his companion Leela (Louise Jameson) by his side, the Doctor (Tom Baker) comes face-to face with the sobering realization that the Fendahl, a terrifying creature born out of the depths of Gallifreyan lore, is, in fact, quite real. In the meantime, lifeless bodies are dropping like flies, and a group of scientists is growing ever more suspicious that an ancient skull recently unearthed in Kenya has something to do with it.