A father took his family to visit a planet in its formative stages. Its oceans supported primitive plant and animal life. While the father enjoyed such planets, its lack of life on dry land disappointed him. He and his wife were preparing to leave when his son informed him that the environmental unit of their aquarium had died, and that they'd forgotten the spare. He and his wife agreed to let his his daughter release the animals in the aquarium into the ocean, a violation of their civilization's rules.