A series of young women have been murdered, their killer apparently inspired by the macabre writings of the nineteenth-century poet Charles Baudelaire. The police have just one suspect. His name is Christian Vogler.

When Vogler's own wife joins the list of victims, Claire agrees to be a decoy of a different kind, helping the police to gather evidence against their quarry. But as she gets closer to Christian, entering the darkest places of his mind, Claire realises she has to throw away the script she has been given and improvise if she is to establish his guilt - or his innocence.