Père-lachaise Mystery

On a wet March evening in 1890, Odette de Valois vanishes from the Pere-Lachaise cemetery during a visit to her late husband's grave. Her maid Denise fears the worst and knows of only one person in Paris who can help: her mistress's former lover, Victor Legris.
When the frightened girl turns up at his bookshop, Victor reassures her, certain there must be a simple explanation for Odette's disappearance. But as he begins to investigate, he realizes it is a far more sinister affair than he first suspected.