This play is about a group of Catholic monks and an abbot and does involve a theological - actually liturgical - dispute set some time in a future that it now turns out never actually occurred (one in which the Catholic Church apparently did not all but disappear because of its hierarchy's demented obsessions with sex). But that is merely the setting; the point of the story is much more universal and has to do with how people tend to huddle together to find meaning in life; how the relationships formed between different sorts of individuals may in the end be all the meaning there is to life. In the final analysis the monks, a fairly limited lot, are lost without their abbot, who provides the meaning they need in their lives, and he in turn, far more aware than any of the others, and therefore most anguished by their common predicament, is lost without his flock of monks' need of his leadership, which is the only meaning he can grasp in life.
Trevor Howard gives an absolutely magnificent performance. His abbot is intelligent, articulate, cunning and in the end so courageously and purely alone that the final image of him on the screen has stayed with me for years.