IMAGINE a world where everyone lives underground, with no first hand knowledge or experience of the outside surface, and all are served every need of body and mind by an all powerful sustainer of life dubbed The Machine. It’s the world por trayed in “The Machine Stops’, this week's ‘Out of the Unknown play, on ABC-TV at 9.25pm tomorrow. Mankind created The Machine, and now relies on it completely, living con tentedly under its influ ence. For one person, how ever, The Machine is not the complete and only ans wer. Kuna (Michael Got hard) seeks more of life, despite the protests and warnings of his mother, Vashti (Yvonne Mitchell) — and finally succeeds breaking through to the surface of Earth. The sights and sounds experienced deepen his re bellion against the present way of life and, although dragged back underground by the forces of The Machine and treated with ridicule by his fellow be ings, he determines to con tinue his struggle for new freedom. The story was written by BE. M. Forster and produced by the BBC, Yvonne Mitchell as Vashti,