I have just finished 'Illuminations' by Mary Sharrat, about Hildegard von Bingen. A reader might be surprised that there could be so much plot in a book which is essentially about a woman enclosed firstly as an anchorite, and later as a nun. However the enclosed nature of her life brings Hildegard into conflict not only with her 'captors' but also with those with whom she shares her religious life, and this provides Sharrat with the meat of the novel. It is also a fascinating glimpse into how difficult living the monastic life actually is. There is Cuno, the jealous Abbott, Volmar her conflicted friend, and the young novices she rescues who later turn to bite the hand that feeds them.
Of course what sustains Hildegard is her relationship with the Divine, and her music. What sustains the novel is the fact that we empathise with Hildegard almost immediately - who could not, when she is a child walled up against her will? From the very beginning we follow her through her long life as she strives to build her place within Christendom, and finally founds her abbey.
From a spiritual perspective, the novel is not overly preachy, but rich with quotations from Hildegard's songs and writings, used appropriately through the text. We witness the 'greening'of her life as she becomes more accepting and less resistant to her lot, and as she grows in maturity casting off the selfishness and egotism of material concerns. Highly recommended.
Other novels I have read that feature diverse women and their spirituality are:
The Chymical Wedding is about alchemy as a way of spiritual transformation and is set in Victorian England. Evensong picks apart episcopal ministry in a small Virginian town in the USA. The Mists of Avalon explores Arthurian legends and how the Pagan Priestess Morgaine copes with the new religion of Christianity. The Red Tent is about women's mysteries in the Bible, told through the life of Dinah.
These are all excellently-written books which will provide a great plot, plus spiritual depth and food for thought.
Please do recommend more in this vein, that you feel I would like.