An English village parson suspects the existence of a concealed and momentous truth of Christian history. He pursues his suspicion by joining an archaeological project in the Sudanese desert, led by an acclaimed expert in early Christianity, who entrances him with her disarming candour and feminine charm.
Tantalising clues to her Christian allegiance are laid throughout the narrative, but he does not discover her denomination until shortly before leaving the Sudan.
He returns to England with a disputatious view of the biblical Jesus, which discomforts his bishop. Episcopalian embarrassment is averted when he leaves the ministry and accepts a university lectureship in Christian History.