Chief Inspector Antonio Lazzaro returns to Italy to take charge of the Homicide Division. There, he must team up with his ex-lover and colleague Simona Colli and the forensics team to solve a series of seemingly unrelated murders. At the crime scenes, however, cryptic clues from Dante's "Divina Commedia" are found that puzzle the investigators. It soon becomes a race against time for Lazzaro to catch the serial killer.