Enzo Macleod, a Scottish teacher of forensics at Cahors in southwest France, has been using his expertise to crack seven notorious murders described in a book by Parisian journalist Roger Raffin. Having solved the first two, Enzo is diagnosed with a terminal illness, and now he is running out of time to crack the most confounding murder of all. But before he can begin, his daughter is nearly killed, while Enzo himself is mugged - and then arrested, in what appear to be a series of pre-emptive strikes by killers desperate to protect their secrets. Destroying his character, framing him for murder ... they will stop at nothing to halt Enzo, who must use all his forensic skills to solve the case - before they succeed.