A family travels in their starship to a planet in a very formative stage. There are oceans filled with plants and primitive animals. The land, however, is barren. The father of the family, while normally enjoying such worlds, is disappointed. His wife is not, as she expected a poor world. When they've decided they've seen enough, they prepare to leave. However, their children come out of the ship, and announce that the environmental unit of their aquarium has died, and they have forgotten the spare. After some pleading, the father agrees to let his children empty the aquarium to give the animals a chance. This is against the rules of their home planet, so they agree to keep quiet.