The Doctor takes Amy Pond and Rory Williams to an idyllic colony built on the only surviving tree on the planet. It is a single giant tree that sustains all life on the planet. It's not long, however, before the colony is attacked by a swarm of Pulpavores. They are large, flying, winged creatures. The Doctor brokers a peace. He points out that the colonists, when they arrived, upset the ecosystem. Working with the Pulpavores, the colonists may even eventually reseed the forest. He leaves the two sides talking.