There is something special about the ancient cathedral in Chartres, with its mismatched spires and strange labyrinth. And there is something special too about Agnès Morel, the mysterious woman who is to be found cleaning it each morning.

No one quite knows where she came from - not the diffident Abbé Paul, who discovered her one morning twenty years ago, sleeping in the north porch; nor lonely Professor Jones, who pays her to tidy his chaotic house; nor Philippe Nevers, whose baby nephew she cares for. And yet everyone she encounters would surely agree that she has touched their lives in subtly transformative ways.

But with a chance meeting in the cathedral one day, the spectre of Agnès' past returns, provoking malicious speculation from the local gossips. As the rumours grow uglier daily, Agnès is forced to confront her history and the mystery her origins finally unfolds.