The school sends ziqi to participate in a training class in the city in order to improve his scores in the upcoming mathematics league competition. . The school's money is controlled by the "rainbow paradise" , which is a symbol of the moon, and . the moon's presence is a sign that something is going on between sister and sister-in-law, and that someone is trying to exploit the "odd sisters." . , the handwriting on the wall is not his sister's, but that of a man who has been in the school for ten years. The handwriting is not .