Viale provided the answer for him, which was interesting of itself. “Not in three years. And you haven’t even asked. That looks bad.”

“Promotion’s not everything,” Falcone replied, knowing his answer sounded feeble. “Some of the most important people we have are just plain street cops who’ll never move up the ladder in their lives, or expect to. Where the hell would we be without them?”

Viale leaned along the table and breathed booze fumes in his face. “We’re not talking about them. We’re talking about you. A man who looked like he was going far. And now he’s treading water. Worse, he’s making bad decisions. Backing the wrong people.”

Falcone bristled. He’d an idea now where this was leading. “By which you mean…?”

“Shit,” the grey man hissed. “You know damn well. You’re getting sentimental in your dotage, Leo. You’re looking out for people who don’t deserve it. This Peroni idiot, for one thing. If it wasn’t for you he’d be out of the force without a pension. With good reason, too. Why’d anyone with any sense stick up for a guy like that?”

Falcone thought carefully before answering. “They asked my opinion. I gave it. Peroni’s a good cop, whatever happened in the past. We can’t afford to lose people of that calibre.”

“Peroni’s a disaster waiting to happen. Him and that partner of his. And don’t tell me you never stuck up for him. Hell, if it wasn’t for you those two wouldn’t even be working together.”

None of this was SISDE’s business. It infuriated Falcone that he was getting a lecture on personnel issues from someone outside the force. He’d be damned if he’d listen to it from anyone inside either. Costa and Peroni were on his team. It was his call who worked with whom.

“These are two lowly cops on the street, Filippo. They’re my problem. Not yours.”

“No. They are two time bombs waiting to destroy what’s left of your career. Peroni’s going to go off the rails again before long. Mark my word. And the Costa kid…” Viale leaned forward and said this quietly, as if it were a confidence. “Come on, Leo. You know who his old man was? That stinking Commie who caused us no end of trouble when he was alive.”

Suddenly Falcone recalled the memory that had been eluding him. Some fifteen years earlier Nic Costa’s father, an implacably incorrupt Communist politician, had exposed a series of financial misdeeds inside both the civilian and military security services. SISDE in particular came out badly. Heads had rolled as a.result. A couple of fall guys even found themselves briefly in jail.

“What on earth has that got to do with the son?” he asked.

“There’s trouble in the blood,” Viale muttered. “People like that have got ideas above their station. Be honest with yourself. You know it as well as I do.”

“These are internal police matters,” Falcone replied sharply. “You don’t have to concern yourself with our business.”

“I’m concerned with you, Leo. People are taking note. They’re starting to wonder. In this business you’re either moving up or moving down. No one stands still. Which way do you think you’re going right now? Huh?”

He leaned close, wreathed in grappa fumes, to make sure his last point struck home. “Where I am everyone moves up. You know why? This is our world. We own it. We have the money. We have the power. We don’t need to go squeaking to a committee of bureaucrats so we can use it. We don’t have to worry whether some asshole of an MP is going to start shooting his mouth off in parliament about what we do. Not anymore. You’re a man who wants results. That’s what I like about you. We’ve got opportunities for someone like you. Ten years down the line you’re still going to be employed too. Which, given how things stand…”

Viale paused and, with an unsteady hand, poured the remains of Falcone’s glass into his.

“… isn’t the case where you are now. Listen to a friend, Leo. These last few years I’ve been offering you a job. That’s not what’s on the table now. Now I’m throwing you a lifeline. One that could pull you out of all the crap you’re swimming in. Before it’s too late.”

Falcone’s cell phone rang. He excused himself, answered it, listening carefully to the familiar voice.

“I’m needed,” he said when the call ended.

Viale’s face creased in a drunken sneer, one Falcone found faintly amusing. “What is it? Some tourist got mugged again down the Colosseum? The Kosovans getting uppity about who rules the hooker trade?”

“Not exactly,” Falcone replied, smiling, getting to his feet, reaching for his camel-hair coat, doubting it really would keep out the cold on such a night. “It’s much more important than that. Excuse me.”

Viale raised his glass. “Ciao, Leo. You have until the New Year. After that you’re on your own.”

THEY LEFT THE CAR where it was, tyre-deep in drifting snow in a blocked dead end off the Corso, and walked to the Piazza della Minerva through a squally wind. The weather changed by the moment. Briefly, through a clear patch high overhead, a full moon illuminated billowing banks of heavy cloud scudding over the city. The stars shone, bright and brittle in the thin winter air, possessing a piercing clarity that was almost painful.

Then the blizzard returned, and the three men pulled their collars around their faces and turned the corner into the small square, where the plain, brute cylinder of the Pantheon’s rear wall loomed above them, luminous under the night’s silver light. It was a sight Nic Costa had never expected to see. The vast hemisphere of the dome, the largest in the world until the twentieth century, so vast that Michelangelo had made the diameter of St. Peter’s dome half a metre smaller out of respect, was now swathed in snow, cutting an unmistakable semicircle out of the sky, like the meniscus of a gigantic new moon rising above the dark urban horizon.

Costa cast a glance at Bernini’s famous elephant in front of the church. The creature was almost unrecognizable. A heavy drift had engulfed the statue and the foot of the diminutive Egyptian obelisk that sat on its midriff. A perfect, miniature mountain rose up from the ground to form a triangular peak, surmounted by the bare needle-like pinnacle of the column, etched with impenetrable hieroglyphs. Sandri snapped some more pictures. Peroni shook his head. Then they carried on, walking parallel with the eastern wall of the Pantheon, into the small, rectangular open space of the Piazza della Rotonda.

Costa felt he knew every inch of the piazza. He’d arrested pickpockets working the busy summer crowds who had flocked to see the impossible: an imperial Roman temple unchanged in its essential form over almost twenty centuries. And a sight that, just as important to many, was free, since Hadrian’s original shrine to every last god in the heavens had in the seventh century been converted into the consecrated church it still remained. Once, Costa had picked up a drunk who’d fallen asleep beneath the spouting mouths of the comical dolphins and fauns of the fountain opposite the temple’s massive, colonnaded portico. But long before he became a cop, when he was just a school kid, full of awe and passion for the history of his native city, he’d come here whenever he could, just to sit on the steps of the fountain and listen to water trickle from the dolphins’ beaks like liquid laughter, just to stare at the way everything changed in the shifting light of the day and the season, feeling two thousand years of bustling history brush up against his face.

Tonight, however, he scarcely recognized the place. The blustering northerly wind was funnelling down the narrow alleys facing the piazza, cascading new and fallen snow straight into the square and the mouth of the Pantheon’s portico. Curious, organically shaped drifts clung to the fountain. The streams of water from the dolphins’ and fauns’ mouths were now frozen solid, like lumpen jewels gleaming in the moonlight.