‘That doesn’t sound possible,’ said Ezio.

‘Only one way to find out, and that’s to make it,’ said Leonardo. ‘Luckily these Venetian assistants of mine are expert engineers. We’ll get down to it straight away.’

‘What about your other work?’

‘Oh, that’ll keep,’ said Leonardo airily. ‘They all think I’m a genius and it does no harm to let them – in fact, it means they tend to leave me in peace!’

In a matter of days the gun was ready for Ezio to test. For its size, its range and power turned out to be quite extraordinary. Like the blades, it was designed to attach to the spring-mechanism which strapped to Ezio’s arm, and could be pushed back to conceal it, shooting out in an instant when required for use.

‘How can it be that I never thought of something like this myself?’ Leonardo said.

‘The bigger question,’ Ezio replied wonderingly, ‘is how the idea could have come to a man who lived hundreds of years ago.’

‘Well, however it came about, it’s a magnificent piece of machinery, and I hope it serves you well.’

‘I think this new toy comes at a most timely moment,’ said Ezio, earnestly.

‘I see,’ said Leonardo. ‘Well, the less I know about it the better, though I can hazard a guess that it may have something to do with the new Doge. I’m not much of a politician, but sometimes even I can smell skulduggery.’

Ezio nodded meaningfully.

‘Well, that’s something you’d better talk to Antonio about. And you’d better hang on to that mask – as long as it’s Carnevale, you should be safe on the streets. But remember – no weapons out there! Just keep it up your sleeve.’

‘I’m going to see Antonio now,’ Ezio told him. ‘There’s someone he wants me to meet – some nun called Sister Teodora, over in Dorsoduro.’

‘Ah! Sister Teodora!’ smiled Leonardo.

‘Do you know her?’

‘She’s a mutual friend of Antonio’s and mine. You’ll like her.’

‘Who is she, exactly?’

‘You’ll find out,’ grinned Leonardo.

Ezio made his way to the address Antonio had given him. The building certainly didn’t look like a convent. Once he’d knocked and been admitted, he was convinced that he’d come to the wrong place, for the room he found himself in reminded him more than anything of Paola’s salon in Florence. And the elegant young women who came and went were certainly no nuns. He was about to put his mask back on and go when he heard Antonio’s voice, and moments later the man himself appeared, leading on his arm an elegant and beautiful woman with full lips and sultry eyes, who was, indeed, dressed as a nun.

‘Ezio! There you are,’ said Antonio. He was slightly drunk. ‘Allow me to introduce… Sister Teodora. Teodora, meet the – how shall I put this? – most talented man in all Venice!’

‘Sister,’ said Ezio bowing. Then he looked at Antonio. ‘Am I missing something here? I’ve never really seen you as the religious type.’

Antonio laughed, but Sister Teodora, when she spoke, was surprisingly serious. ‘It all depends on how you view religion, Ezio. It’s not men’s souls alone that require solace.’

‘Have a drink, Ezio!’ said Antonio. ‘We must talk, but first, relax! You’re perfectly safe here. Have you met the girls yet? Anyone take your fancy? Don’t worry, I won’t tell Rosa. And you must tell me -‘

Antonio was interrupted by a scream from one of the rooms that surrounded the salon. The door flew open to reveal a wild-eyed man wielding a knife. Behind him on the blood-soaked bed, a girl writhed in agony. ‘Stop him,’ she screamed. ‘He’s cut me and he’s stolen my money!’

With a furious roar the maniac grabbed another girl before she could react and held her close, his knife at her throat. ‘Let me out of here or I’ll carve this one up too,’ he bawled, pressing the tip of the knife so that a little bead of blood appeared on the girl’s neck. ‘I mean it!’

Antonio, instantly sober, stared from Teodora to Ezio. Teodora herself was looking at Ezio. ‘Well, Ezio,’ she said with a coolness that took him aback, ‘now’s the chance to impress me.’

The maniac was making his way across the salon to the door, where a small knot of girls was standing. As he reached it, he growled at them, ‘Open it!’ But they seemed rooted to the spot with fear. ‘Open the sodding door or she gets it!’ He dug the knife a little further into the girl’s throat. Blood began to flood from her neck.

‘Let her go!’ commanded Ezio.

The man swung round to face him, an ugly expression on his face. ‘And who are you? Some kind of benefattore del cazzo? Don’t make me finish her off!’

Ezio looked from the man to the door. The girl in his arms had fainted, a dead weight. Ezio could see the man hesitate, but any moment now he would have to let her go. He readied himself. It would be hard, the other women were close; he’d have to pick the precise moment and then act fast, and he knew he had very little experience of his new weapon. ‘Open the door,’ he said firmly to one of the terrified prostitutes in the group.

As she turned to do so, the madman let the bleeding girl fall to the ground. As he prepared to rush out into the street, he took his attention off Ezio for a second, and in that second Ezio released his little pistol and fired.

There was a snapping report and a burst of flame followed by a puff of smoke seemed to shoot out from between the fingers of Ezio’s right hand. The maniac, a surprised expression still on his face, fell to his knees, a neat little hole in the middle of his forehead and some of his brains spattered on the doorpost behind him. The girls screamed and moved hastily away from him as he slowly toppled forward. Teodora shouted orders, and attendants hurried to succour the two wounded girls, but they were too late for the one in the bedroom, as she had bled to death.

‘You have our gratitude, Ezio,’ said Teodora, once order had been restored.

‘I was too late to save her.’

‘You saved the others. He might have slaughtered more if you hadn’t been here to stop him.’

‘What sorcery did you use to bring him down?’ asked an awe-struck Antonio.

‘No sorcery. Just a secret. A grown-up cousin of the throwing-knife.’

‘Well, I can see that it’s going to come in handy. Our new Doge is scared stiff. He surrounds himself with guards and he never leaves the palazzo.’ Antonio paused. ‘I imagine that Marco Barbarigo is next on your list?’