The Doctor and Susan arrive on a jungle world, where they discover the remains of a crashed colony spaceship and a row of graves, all old except for one that has been freshly-dug. They meet a salvage operative named Bethan, who has locked herself inside her space-suit to protect herself against the clamour of the jungle while she waits for the return of her missing partner, Tino. Realising that the new grave belongs to Tino, the Doctor and Susan take the woman back to her own ship to rest; however, they soon find themselves succumbing to the effects of the jungle, losing their will to leave as they are watched by strange arboreal creatures in the trees. The Doctor, Susan and Bethan soon discover that Tino is still alive, having been regressed into a primitive state by the planet’s ecology, and is now living with the arboreal creatures, some of whom are the original colonists. Bethan elects to remain with Tino, while Susan leaves with her grandfather, knowing he will soon become bored with paradise...
- The TARDIS takes the form of a tree stump.
- This short story accompanied a chapter about evolution.
to be added