Summary
In the story there was a boy who loved to imagine. One day he found a fish at the shore and imagined it to be a mermaid. He took the imaginary mermaid to his home and showed it to his parents. However, free imagination was prohibited in his country,so not only his parents but the whole country denied the boy's imagination. He was forced to erase the imaginary mermaid from his brain. Nevertheless, the boy was able to maintain his imagination through reading books. The story ended with the boy disappearing into the endless ocean with his imaginary mermaid.
Message
I think what Tezuka Osamu wanted to convey through this animation is the importance of literature. No matter how strict the society prohibits a person from imagining, literature can give numerous tips of getting free imagination. The role that literature plays in people's life can be extremely big.
I have heard of a woman who survived the Holocaust because of drama. Life at the concentration camp gave her no freedom physically and mentally. She could have lost the will to live at any moment. However, she thought of saying the lines from the dramas that she remembered aloud. The woman and the people around her started to enjoy the time of acting out the dramas which offered them the vitality.
Endiing
I think the sea that is stretching endlessly to the horizon is symbolizing people's bottomless brain. Even though the adults tried to control the boy's way of thinking, they failed in doing so. The boy was able to find a way to freely imagine within himself. Nobody can dye the blue sea completely red. In the end, the only person who can control your brain is you.
