Lent 1977 is a particularly penitential season for Catholic priest Andrew Boulton. Attempting to be faithful to the Church to which he converted at Cambridge, he finds himself trying to steer an even path in the troubled waters following the Second Vatican Council. On the one hand, he is being courted by traditionalists in the shape of his old mentor Monsignor Charlie Payne and the devious Tridentine seminarian Aelred Blair, On the other hand he is being persecuted by the newly appointed area bishop Michael Follett who regards him as an awkward relic of the past. He attempts to escape from all this by devoting himself to his parish and particularly to helping a young parishioner with dyslexia, but, as the weeks progress, he finds himself increasingly overwhelmed, his anguish reflected in the unfolding Lenten liturgy. The climax takes place on Maundy Thursday night with a great act of betrayal.