Centuries ago, a Zygon spaceship crash landed in Loch Ness. Their most powerful weapon is a huge armoured dinosaur-like creature of terrifying power that they brought to earth as an embryo - the Loch Ness Monster.UNIT faces one of its toughest battles as Broton, Warlord of the Zygons, puts his plan into action and the Loch Ness Monster attacks.