The Terran Survey Vessel Excelsior, commanded by Louis B Frederick, lands on planet UX-4732. They find the TARDIS nearby. The Doctor steps out to greet them. He introduces them to a primitive but rather idyllic village populated by deaf, mute humanoids. They witness a procession in which the villagers carry animal carcasses onto an altar, standing on a structure that looks like a giant spiderweb. It turns out to be just that. An enormous spider emerges from a nearby cave and begins encasing the villagers in cocoons.