The first volume of Riley’s trilogy, A Vision of Light introduces the intrepid Margaret of Ashbury in 14th-century England. Married to an inventively cruel husband, Margaret finds escape in the arms of the Black Death, left by the roadside as her husband escapes London on horseback.
But there is comfort even in the throes of despair. Doubting her faith, Margaret receives a Vision of Light and with it the gift of healing, a power she keeps to herself, using it only sparingly and in the most extreme circumstances as it depletes the life force from her body.
Nursed back to health in the countryside by an aged herbalist/midwife/ healer, Mother Hilde, Margaret is trained in the healing arts as well as midwifery, the two journeying to a local estate to help in a noblewoman’s impending birth, one that is fraught with danger for mother and child.
Escaping the noble house with a band of traveling entertainers, the group turns toward London where they separate. Mother Hilde and Margaret remain with Sebastian, an alchemist seeking the Secret of Life in their humble abode on Thieves Alley. Sebastian assumes the name Brother Malachi, hoping the group might appear more conventional but still the wagging tongues of neighbors.
With Brother Malachi’s sleight of hand (this is Thieves Alley, after all) and the efforts of the two women in midwifery and herbal remedies, their fortunes improve. Margaret comes to the attention of a successful older merchant who offers her a life of substantial comfort. His wealth also provides Margaret with another gift: she hires Brother Gregory, a young man of noble family who is seeking God, hiring meanwhile as a transcriber.
It is to Brother Gregory that Margaret reveals her extraordinary experiences, her first marriage and supposed widowhood, an assault by that evil husband who must be sure she is forever out of the way, and an examination by Inquisitors ever hungry for souls to save.
Brother Malachi is riddled with contradictions. His father frequently requires his return to the family estate to resolve conflicts, and his search for God is filled with frustration and a low opinion of women, including Margaret, that is dismissive of her female attributes, furious that such as she should be given the gift of healing: “Women and trade - they pull a man down from the life of the mind.”
One more request sends Brother Gregory over the edge: Margaret wants to learn to write, a mission that is deeply offensive to Gregory, although he grudgingly respects Margaret’s fortitude as revealed in her extraordinary tale. Shadowed by the Inquisition, such as being readily accused as practitioner of the Devil’s Art, Margaret barely escapes her inquisitors, facing widowhood and the plunder of her fortune at the end of this tale, riding into the unknown without a backward glance at her beloved home but with two more volumes of adventures ahead.