This William Hartnell-era episode of DOCTOR WHO finds the Doctor and his fellow travelers on-board the Tardis landing on an alien planet. They quickly discover that the friendly inhabitants of the planet, the Menoptra, are slowly being destroyed by a malevolent presence known as the Zarbis. The Zarbis are capturing the planet in a giant web, thereby killing off the Menoptra and creating a powerful force that won't allow the Doctor and his allies to leave. Together with the Menoptra the Doctor must figure out how to defeat the Zarbis before it's too late.