 400 000 years ago, an inter-stellar civilization looking for intelligent life finds Earth. A group of scientists are sent to test the human beings living on Earth, to determine how fast they will evolve, without interfering in their development. Prometheus, a young soldier, and Athena, a wise scientist, are part of the team. This is the story of the last day of their mission on Earth, a day that proves to be fateful for the human race.