Philip and Ruth have a rock-solid marriage. Despite the demands of Philip's busy West Country parish, the challenge of bringing up three children, and the pressures of modern life, they take strength and comfort from each other, and from the support of the local community.
So when Philip starts spending so much time with Louise Kenton, Ruth thinks nothing of it: after all, he's simply doing his pastoral duty by offering tea and sympathy to one of his parishioners.
But Louise's vulnerability proves a powerful temptation. Gradually, Philip finds himself plummeting towards tragedy, as he is drawn into a relationship that makes him question all his most cherished beliefs, putting at risk everything that really matters to him - his wife, his family, his faith . . .