Some people think Genesis Children don’t has a plot at all but there is a at least some kind of central theme: A priest who teaches at the international school in Rome puts an advertisement in the local paper which is designed to entice boys from the school who are bored, or at least not content, and rebellious enough to take off on their own and skip school. The advertisement is in English, therefore all the responses are from English speaking students at the school. The priest plants the advertisement where one particular student will find it, but the other seven come across it on their own. 

When the eight boys (ages about ten to sixteen) arrive at the place indicated by the advertisement, they are lead to a secluded stretch of beach and left on their own for about a week. The Priest leaves one box of food, but does not tell the boys it is there. He does indicate by what he tells the boys when they first arrive that he expects them to learn something by way of this adventure, but is very ambiguous as to what he expects them learn. The movie is narrated by one of the boys, and if you pay attention to what he is saying, you will see something of what the boys are learning, or at least something of what they are thinking.