Julia Garnet, recently retired spinster school teacher from Ealing and communist party member, loses her only friend. She throws a lifelong habit of caution to the winds and takes up residence in Venice. In spite of her atheism, she becomes fascinated by the city's religious architecture and art, and especially the story of Tobias and the Angel, depicted in the paintings of the Chiesa dell' Angelo Raffaele.

A doomed love affair with a charming Italian breaks down her self-constructed barrier against intimacy, and she becomes involved with people – their sufferings, problems, and intrigues. Her long-repressed emotions are released and she learns at last how to live life to the full and how to embrace death.

This story is not just about one individual's life. It touches on a reality beyond the world of the senses: principalities and powers, and the age-old battle between good and evil in which Miss Garnet has a role to play.