In their fifth outing, Antoine Verlaque and Marine Bonnet are searching for a murderer – in a crime connected to Provence's greatest artist.
A friend in his cigar club asks Antoine to visit René Rouquet, a retired postal worker who has found a rolled-up canvas in his apartment. As the apartment once belonged to Cézanne, Rouquet is convinced he's discovered a treasure. But when Antoine arrives there, he finds René dead, the canvas missing, and a mysterious art history professor standing over the body.

When the painting is finally recovered, the mystery only deepens. The brushwork and color all point to Cézanne. But who is the smiling woman in the painting? She is definitely not the dour Madame Cézanne. Who killed René? Who stole the painting? And what will they do to get it back?