After ninety minutes, a soft chime from his comm-watch informed Alex that he had been still for too long. He shut the holo with a word, stood up and stretched, replacing the plastalloy brace over his loose-fitting trousers. Awkwardly, he climbed the steps out of the boat onto the gangplank that connected his floating home to the cobbles of the walkway, feeling increased humidity in the air.

Later, he thought, there would be a storm. Rain might fall. The city might be cleansed.

He squinted towards the top of the steps. Profiled by the sun, the civilian security guard was talking to the man that drove the lightweight electric disinfectant truck. He recognised neither of them. Was it likely both had been replaced?

He swung his stiff left leg over the gunnel. A seagull flew up and Alex swayed back. In the same moment, a shot rang out and Alex’s subconscious and conscious mind began making calculations, stretching time, separating three sounds. The first was a whine, like a mosquito, but a mosquito moving at several hundred metres per second.

The second was a clang as the projectile struck the superstructure of the boat, perhaps the rail that Alex’s hand had just left, or maybe the grill of the walkway connecting the boat to the shore. Then a third sound, from further away and out of sync – the detonation inside the weapon whose soundwaves had taken X amount of time to reach him.

In the end, it didn’t matter. The order was immaterial. They were so close together, the three distinct noises, that only someone with extensive experience of firearms would recognise them for what they were, which was why Alex was already lying flat on the cobbles, in the narrow band of shadow cast by his boat, edging closer to the water, the slimy gap between the hull and the stonework of the bank, calculating trajectories and likely vantage points and probable enemies.

No, that question was irrelevant. It didn’t matter who. Not at this point.

A second shot and another set of three distinct noises, striking stone not metal, and from a different angle. Different enough to indicate a second shooter or the same person having moved?

Alex edged closer to the water, improving his cover, feeling the gritty cobbles under the heels of his hands.

The two shots had come from close together but from above. High above. He was only uninjured because the seagull flying up had made him sway back, arching his back, taking him out of the line of fire. Wherever the shooter was, they needed not to attract attention. They couldn’t release a volley of six or twenty projectiles.

Where, then?

The platform at the top of the Bastille Tower? That was possible and would also provide enough angle, from one side to the other of the circular platform, for the difference between the two shots. And it was a location that it would be possible to seal off, temporarily at least. In fact, hadn’t he seen that happen, the worker in his hi-vis vest with his plastic barrier?

From the shadow between the hull and the bank, half his body hanging down towards the water, Alex tried to send a back-up request from his comm-watch.

Nothing.

That was ridiculous. He was close to the data hub inside his boat. Even if that were disabled, he was in the city centre, surrounded by a dense mesh of wifi signals. If his comm-watch was off grid, it was because someone was jamming his signal, maybe broadcasting white digital noise. But where from?

Maybe the electric disinfectant sprayer? That was big enough to house the necessary equipment. And, if there was someone close enough to jam his comms, they were also close enough to provide a second line of attack.

No sooner had he worked that out, than the second line of attack began with another shot – the same whine, the same detonation, but another impact of projectile on stone rather than metal, close to where he lay half-concealed, safe-ish but not safe enough.

Alex let himself slip down into the gap between the hull and the bank, holding tight to a rusty metal mooring ring, allowing his body to slide into the sludge-green basin water, oddly viscous – or was that a psychosomatic thing because it felt unclean, semi-stagnant, inhabited by all kinds of scavengers of organic waste? He let himself sink further, joining that ugly soup, taking a deep breath, the water closing over his head. He pushed down beneath the hull, scraping his knuckles on the shells of the molluscs that clung to it despite the anti-foul paint, finally finding himself in the cavity between its twin chambers, a design that gave the craft stability, but providing another advantage, too – an air pocket between the hulls.

He came up with his chin just above the surface, treading water with his one good leg, sealed from the surface, in a gap big enough to keep him safe for ...

How long?

Twenty minutes, perhaps, before the carbon dioxide exhaled by his lungs began to poison him with each new breath.

The boat lurched above his head. Someone had climbed on board, someone looking for him, obviously. Maybe the man from the electric disinfectant truck? Maybe the unknown security guard? How hard would either of them be to impersonate? Violence wouldn’t necessarily be required. It would be enough to give the real guard a food voucher for a restaurant in the restricted zone or a travel permit for somewhere special – plus instructions not to come in to work today.

And, by the way, I will need to borrow your uniform.

Alex felt his good right leg beginning to ache with the effort of keeping his chin above water in the narrow gap. Then the boat rocked a second time.

Alex could visualise the intruder, stepping from one side of the hull to the other, looking for a tell-tale splash in the water – ripples or bubbles, indicating where he was, maybe a disturbance as he kicked away, holding his breath, swimming underwater to the cover of the narrowboats moored on the opposite bank.

Worried the beating of his right leg might give him away, Alex manoeuvred himself closer to the stern, finding a handhold in one of the openings for the water-jets that the boat used for forward propulsion.

Clinging to it, he was able to relax, frustrated that he couldn’t activate the high-voltage defences, making the rails and handholds live, but to do that he would need to connect to the boat’s ...

He realised his comm-watch was glowing in the pitch-dark space. He had a faint connection. How was that happening?

Yes, of course. Concealed in the pocket of air between the twin metal hulls, he was in a kind of protective steel pod, out of reach of the jammer but only a metre or so away from the data hub on board.

Boosted by the boat’s systems, he used the enhanced remote capabilities of his comm-watch – another upgrade from ‘a grateful nation’ – to search for adjacent devices in the surrounding miasma of electromagnetic radiation, finding the jammer integrated into the disinfectant truck, as he’d guessed. With a word of command, he told his comm-watch to piggy-back the signal and power the truck down. Once that was done, it took only seconds to restore maximum connectivity.

He spoke a command: ‘Defence.’

A set of three options appeared on the large square face of his comm-watch. A couple of months ago, he might have said: ‘Dissuasive.’ Or, if he felt the danger was significant enough, he might have said: ‘Severe.’

Not now, though. Not since he had faced a conspiracy determined to create devastation through famine and war, those evil old twin Gods.

‘Lethal,’ he said.

The comm-watch asked him to confirm.

Yes / No.

Of course, for the lethal electric charge to take effect, the intruder would have to have a hand on a rail or a window frame or some other metallic element of the boat’s superstructure – he was safe holding onto the fibre-glass hull – an element capable of carrying a fatal combination of current and voltage, enough to stop someone’s heart.

But he already knew that must be the case from the way the boat’s hulls were slightly slewed to one side, his attacker leaning out, balancing their weight above the oily surface of the water by grasping the length of tube steel that ran the length of the deck.

He gave his confirmation.

Yes.