Twenty years ago, a mysterious group called the Butteri committed a series of bizarre crimes evoking the lost race of the Etruscans. Now a politician is found ritually murdered, seemingly by a strange young man dressed as the Etruscan blue demon, detective Nic Costa suspects that the old case was never really solved. The Butteri have returned - and are planning to unleash a devastating sequence of attacks on the city. As Costa and his team start to dig deeper into the past, there are still too many questions left unanswered - and much more to the history of the Butteri than anyone wants to admit.