In this episode, scientists arrive at a small barren planet in search of life. Two explorers enter a cave and encounter an anomaly. In the process of beginning the transmission of sensory data to the base station, they are overtaken by a series of psychological and physical transformations. They feel a strong emotional charge from the anomaly and try to describe to one another the nature of the phenomenon.
Back at the base, the scientists begin analyzing the datastream and are stunned to discover that it appears to be a message from an intelligent entity. The message seems to be telling a story from deep in time about the history of the planet told from the perspective of the planet itself and its atmosphere.