The Mona Lisa has hung in the Louvre for five hundred years. Now they are going to move her, and something inside the paint has been counting the days.

Claire Ashworth is the best provenance specialist in London and the least employable, blacklisted for telling expensive truths about beautiful things. Then the Louvre offers her a year's money for ten days' work: vet the world's most famous painting before its relocation to a new room.

The custody file is perfect. Too perfect. And threaded through it, century after century, is a family name the record seems to have been saving for last. Her own. The museum's chief conservator has vanished into a leave of absence no one will explain. A collector with amber eyes has been waiting a very long time for exactly this week. And her grandmother, two years dead, has left her a postcard written in ink that has not dried: Don't let them move me.

Florence, 1503. Leonardo da Vinci begins a portrait he will never deliver. He will keep her beside him for sixteen years, carry her over the Alps in the ice, and refuse a king's fortune for her, because the painting is not a portrait. It is a prison built as a question with no answer, and a bloodline was bred to guard it.

The move is Thursday.

A Painted Souls novel, readable as a standalone supernatural thriller: the whole cipher in one volume. For readers of Dan Brown and Elizabeth Kostova's The Historian.