The film shows us the daily life of a normal boy when he discovers something lost on a beach and tries to get it back to where it truly belongs. Further, there are a lot of meaningful details that we need to think about.
From the beginning, the limited grey and brown colors indicates the heavy industrialized city. The city is so dull and rusted. Because of the heavy industrialization, there are no plants which directly show that the entire city is tired and lacking vigor. Living under the bad environment, people in this city are doing their works emotionlessly just like walking dead, ignoring unusual things around them. I think the author is trying to tell us the world is cold and selfish.
The lost creature is in bright red color which distracts the boy from collecting bottle tops. Different with those people’s ignorance, the kid noticed the lost creature and has a strong desire to figure out what is it. Asking people on the beach, the kid cannot get the answer from them since no one cares to notice this odd creature. After he brings it back home, his parents are too busy to notice. From this clear contrast between kids and others, the film wants to tell people that we need to have some curiosity and insight into those unusual things in our life just like that kid and should not just focus on the common things.
After walking along the industrialized street, the boy finally finds the place that the lost thing may belong to, which is a very colorful world compared to the grey and brown mechanic city. This is a vigorous space with lots of lost creatures indicating that the thing belongs there. At the end, as the boy grows up and begins to work, he gradually becomes the person just like others, losing all the good characteristics of a child.
In conclusion, I think the film is trying to encourage us to look at the world in a different way, and encourage us to notice those who are different no matter what they are. We should not ignore them as they may need our help. Furthermore, there are some good characteristics of children, such as innocence, mercy, and curiosity that should not be abandoned as they grow up. This film clearly shows this point through the lens of both children and adults.