The plot of the movie is rather simple. Two children, Sam and Suzy decide to go on a runaway together, both feeling rejected by people. The community of the little island they're living on tried to catch them back.
The movie is enjoyable in several ways. If you're familiar with Wes Anderson (Fantastic Mr. Fox, The Darjeeling Limited...) you can still see the perfect photography, amazing soundtrack and the original set. The acting is still pretty good, I hardly recognize Harvey Keitel as the Chief Scout, Bill Murray is...well...Bill Murray an actor you don't need to comment. The young actors are good too. Seeing Bruce Willis in a simple cop tired but human feel very strange but it does bring something new to the movie.
You can also enjoy the movie for the beauty of the land, one feast for the eyes, it does have some ecologic message in a way, it's a call to preserve and to show the uncanny and strong appearance of the nature.
Top of that, it's a psychological call, some kind of message in the bottle. Reminds you some childhood trouble, when you feel different, when you think the entire world is against you and searching for a place to escape. Far from the real world. Far from the adult world.
Make sure the dream consume your life, for life don't consume your dreams.