A band of thirteen-year-old boys reject the stupidity of the adult world. They decide it is illusory, hypocritical and sentimental, and train themselves in a brutal callousness they call 'objectivity'.
When the mother of one of them begins an affair with a ship's officer, he and his friends idealise the man at first, but it is not long before they conclude that he is, in fact, soft and romantic.
They regard this disillusionment as an act of betrayal on his part - and the retribution is deliberate and horrifying.