In a hushed Vatican reading room, the scene was shocking: a crazed professor shot dead after brandishing evidence of a grisly crime. Moments later, two bodies are found in a nearby church, each with a gruesome calling card from the killer.

In Rome's crowded Campo dei Fiori, a woman rushes up to two carabinieri lounging in their sunglasses and uniforms, insisting that her 16-year-old daughter has just been abducted. Detective Nic Costa sees the scene unfold and intervenes. Because Costa knows what the two officers don't: that in the morgue at Rome's police headquarters, a forensic pathologist is examining the strange, mummified corpse of another girl, whose disappearance and death bear haunting similarities.

It's approaching Christmas in Rome and snow is falling in a way that only happens every 20 or 30 years. The city is soon paralyzed by an unseasonably icy grip, and in the dark corners of the Pantheon a grim and mysterious story begins to unfold.

On their private island, the Arcangelo family defies the world: living in a decaying palazzo, making glass in a terrifying, archaic furnace, watching their absurd exhibition hall sink into disrepair. But now the world is coming to their dying outpost in a crumbling corner of a Venice that tourists never see. Police boats and vaporetti bring investigators, curiosity seekers, and one man who plans to own the property himself. With two family members consumed by the foundry fire, both mystery and opportunity have been bared to the bone.

It begins on one of Rome's least-known hills, the Aventino, in the public piazza fronting the mansion of the Knights of Malta. There, a curious keyhole to the knights' estate reveals an astonishing view, a direct line across the Tiber to the dome of St. Peters in the distance.

In a hidden studio in Rome, an art expert is found dead in front of one of the most beautiful paintings Nic Costa has ever seen - an unknown Caravaggio masterpiece. But before long, tragedy will strike Nic far closer to home. The main suspect's identity is known, but he remains untouchable...

In the gorgeous grounds of Rome's Villa Borghese park the glitterati of the movie world are gathered for a world premiere. A legendary Italian movie director has come out of retirement to create a blockbuster based on Dante's Inferno. But, as Nic Costa and his colleagues attempt to guard the precious collection of historic artifacts attached to the event, the premiere is disrupted by tragedy and a horrific murder. Is a disgruntled admirer of Dante taking his revenge on the cast of the movie?

Twenty years ago, a mysterious group called the Blue Demon committed a series of bizarre and ritualistic crimes evoking the legacy of the lost race of the Etruscans, and leaving in their wake a group of dead students, a murdered couple, a cryptic message and a kidnapped child. Now, the leaders of the G8 are descending on Rome for a summit at the Quirinale Palace.

Detective Nic Costa faces his hardest case yet. When the sins of the past echo the crimes of the present... When British academic Malise Gabriel falls to his death from a Rome apartment, detective Nic Costa suspects more than a simple accident. Nic is sure Malise's family are hiding vital information. As the investigation deepens, Rome’s seedy side is uncovered, revealing a web of deceit, treachery and corruption. The key to the truth lies with the Gabriels.

Detective Nic Costa finds himself a stranger in a strange land when he's sent to infiltrate the mob in a remote part of southern Italy. Roman police detective Nic Costa has been sent undercover to Italy's beautiful, remote Calabrian coast to bring in the head of the feared mob, the 'Ndrangheta, who has offered to turn state witness for reasons of his own. Hoping to reel in the biggest prize the state police have seen in years, the infamous Butcher of Palermo, Costa and his team are aware the stakes are high. But the constant deception is taking its toll....