This is bananas as some might say. A movie that defies a simple explanation. But my summary line above should give you a clue. And still there are so many things that will surprise you, because they are coming from so far left field ... it's amazing what kind of fantasy the writers had who came up with this. It surely could not be one mind could it? I actually didn't check.
Now if you've seen Animes before you may be aware that they are quite complex and this is not different in that regard. It will not be everyone's cup of tea, but if you cherish and indulge the craziness that unfolds, this will be quite engaging. It is hard to capture what happens here in words - so it is better to watch it and get the whole thing.