This is the story of Ruth bas Elazar Saul, a Jewish midwife who returns to her home of Deutz, outside Cologne in Germany. Imbued with the radical ideas of Spinoza and with the ancient Hebrew Kabbalism, Ruth's revolutionary methods of dealing with illness lead to accusations of witchcraft and imprisonment. Her love affair with Detleff von Tennen, a local Catholic bishop, may save her in the short term, but at a time of brutal repression and religious persecution there are few options for those who break taboos.