The movie starts at a beach, where the boy finds a thing.
The thing looks odd and lonely, and doesn't seem to belong to anywhere.
The climax is where he turns the key on the wall, and suddenly there is a bright colorful world of odds and ends before them.
I felt the scene that his friend tried to measure the thing out to define what it was but couldn't, was ironic.
The ball which was popped and thrown away seems to me as a symbol of hope that couldn't be granted. Well, the lost thing, I suppose, represents the small interesting things we think that are worthless.
The theme was about what we have lost in our busy lives which some people haven't even noticed that they have lost it.
