we watched the video called Ningyo (which means "mermaid" in Japanese) in the last class.
One day, the little boy was at the shore, then found the tiny dying fish. He picked it up and released it. Just then, that fish transformed itself into the beautiful mermaid. He brought her to his home to show to his parents. However, what his patents saw in the big water tank was just a tiny fish. Since the boy kept saying that it is a mermaid, people did evil experiments to let him stop imagining. (In his country, imagining was prohibited by it's law.)
After long period, he gradually forgot about what he imagined, then he was brought to the shore to release "the tiny fish". What he saw, however, was that mermaid, not the fish!
I hope he will be able to come to the shore sometimes to see her.
Imagination is the fruit of people all the time, and I suppose that is what Osamu Tezuka wanted to tell us.