There is an island called Kaidan, that is out of touch with the rest of the world. It is mostly populated by high-school students, who ended up there without knowing why.One of them is Nanakusa, who is satisfied with his new life, and sees the island as a paradise. That is until his old love interest Yuu appears at the beach. She is upset with the rules of the island, and wants to organize an escape operation.The first thing to notice is the beautiful scenery, and the cozy town settings. The small-scale world-building activated my imagination and made me want to add more. It is very similar to the anime Angel Beats, with differences. The school in the movie feels more humane thanks to the postgirl and other service personnel.As usual in this genre, one can find holes in the logic if looking closely. Like where does the food come from? Unexplained or skipped parts made me think that it is an abridged adaption of a longer work. It turned out that the base is a novel by Kouno Yutaka.The most engaging character is Yuu. She becomes very emotional sometimes, and cries a lot, which is natural considering how much frustration she must feel.Nanakusa on the other hand was repulsive to me during the first viewing. Since his motivation and intentions are not fully known, it was hard to sympathize with his erratic behaviour. (I dislike him less nowadays.)The weakness of the story is that the psychological and relationship problems are shallow and abstract. Nanakusa and others are spoiled kids who create their own problems in the absence of real problems. That happens sometimes, and can be interesting, but it does not provide high enough stakes and tension to motivate a full movie.The greatest attractions are the mystery and the setting.