Answering a distress call, the TARDIS lands on Chloris, a planet choked with abundant vegetation. Discovering a gigantic, fragmented eggshell that's the source of the call, the Doctor and Romana also find themselves under arrest for tramping about in a zone marked for death. Before they can be brought before Lady Adrasta, the matriarchal ruler, for questioning and ceremonious execution, a roving ban of metal-scavenging bandits attack and run off with Romana.