The episode is set in a lofty plateau created by the collision of Australia (who moved northward) against Japan and Kamchatka (the Asian tectonic plate), 100 million years into the future. The episode focuses on four species: (1) Silver Spider, a descendant of our spiders, the silver spiders live in huge colonies and have a caste system based on the size of the animal. They build massive webs across canyons; (2) Poggle, a descendant of the hamster and the last species of mammal on Earth at this time, prey to silver spiders; (3) Great Blue Windrunner, a brilliant blue bird with wings on its legs which sees in ultraviolet and lives at the highest points on the plateau; (4) Grass Trees, Tree-like plants descended from bamboo.This episode shows how this bizarre food chain works