A UNIT nuclear convoy, stranded on the shores of Lake Vortigern, becomes the focus of an incursion by knights from a parallel reality. In this other world, technology and magic exist side by side, and the legends of King Arthur are fact. Close to the lake, the sinister Mordred battles against his enemy Ancelyn and summons his mother, the powerful witch Morgaine. Is the Doctor really Merlin? And will he discover what actually happened to King Arthur? But time is running out for everyone as Morgaine takes control of the nuclear weapons and summons the Destroyer – Lord of Darkness and Eater of Worlds… This novel is based on a Doctor Who story which was originally broadcast from 6–27 September 1989.


聯合情報小組 (UNIT) 的核武護衛隊在平行時空的英國佛地根湖岸邊擱淺，成了當地騎士的攻擊目標。在這個世界裡，科技和魔法共存，連亞瑟王的傳說都是真的。在湖邊，邪惡的莫德雷德與他的敵人安斯林交戰，並召喚了他的母親，強大的女巫摩根。博士真的是梅林嗎？他會發現亞瑟王真正的遭遇嗎？隨著摩根掌控了核武器，並召喚了世界毀滅者 (Destroyer) ——黑暗之王 (Lord of Darkness) 及世界吞食者 (Eater of Worlds) ，時間變得越來越緊迫。本書根據《Doctor Who》電視影集撰寫，影集原播出時間為 1989 年 9 月 6 日到 27 日。