Her work with Police Scotland’s Complex Crimes Unit has come to an end, she’s been forced to abandon her academic career, and she’s homeless. It looks like she has no options. But then she gets a call from Interpol agent Susannah Roscoe, who needs a forensic psychologist to help crack a perplexing case at the Louvre in Paris. Petra is just the woman. Filled with a new sense of purpose, she travels to Paris and starts to unravel the clues. But as the killer continues to target new victims and Paris police are stumped, can Petra and Susannah crack the case before more people die? Or will they become victims themselves?