Young Inspector Unai López de Ayala, known as "Kraken," is charged with investigating a series of ritualistic murders. The murders are eerily similar to ones that rattled the citizens of Vitoria twenty years earlier. But back then, police were sure they had discovered the killer, a prestigious archaeologist who is currently in jail. Now Kraken must race to determine whether the killer had an accomplice or whether the wrong man has been incarcerated for two decades. This fast-paced, unrelenting thriller weaves in and out of mythology and legends of the Basque country as it hurtles to its shocking conclusion.