'A nickname? What are they calling me?'

'Ms Alien.'

'Oh, heavens. For a while everyone called me Miss Foster, after Jodie played me in that film.' Crowe shook her head. 'Well, why not? So long as I've got a pen for signing autographs. Let's go.'

PEAK SHOWED HER ROUND 02 LEVEL. They'd started their tour in the bow and were making their way amidships. Crowe had admired the gym, crammed with treadmills and weight machines. It was practically deserted. 'Under normal circumstances you can't move in here for people,' said Peak. 'The Independence can accommodate three thousand men. Right now there are barely two hundred of us aboard.'

They walked through the junior officers' berths – dormitories for between four and six people with comfortable bunks, plenty of storage space and foldaway tables and chairs.

'Cosy,' said Crowe.

'Depends on how you look at it. There's not much chance of falling asleep when things get busy on the roof. Those helicopters and jump-jets are roaring up and down the flight deck, only metres above your head. It's hardest on the new recruits. They're exhausted at first.'

'How long does it take to get used to it?'

'You don't. You get used to being woken up, though. I've served on flat-tops before, and you're always away for months at a time. After a while it seems normal to be lying there on stand-by. You forget what it's like to sleep soundly. The first night at home is hell. You're listening out for the roar of engines, aircraft landing and helicopters docking, people running in the passageways, constant announcements – but instead there's just the ticking of your clock.'

They walked past the enormous messroom and came to a watertight door protected by a combination lock. They went into a large, darkened room. For the first time Crowe saw people at work. Lights flashed from consoles as men and women stared at the bank of wide-screen monitors that lined the walls.

'02 LEVEL is where you'll find most of the control and command rooms,' explained Peak. 'In the past they'd have been housed in the island, but that's too risky. Enemy missiles are programmed to strike large heat-emitting structures so the island's an obvious target. They'd only have to score a few hits, and we'd be like a body with its head blown off. That's why most of the control rooms are located under the roof.'

'The roof?'

'Navy jargon. I meant the flight deck.'

'And what's your role on board?'

Peak ignored her.

'This room is the CIC…'

'Ah. The Combat Information Center.'

The eyes in the narrow ebony-sculpted face flashed with irritation. Crowe resolved to keep her mouth shut.

'The CIC is the nerve-centre of the vessel,' said Peak. 'All the information that comes into or goes out of the ship passes through here – data from the ship's sensors, satellites, missile detection, surface-search radar, damage-control, communication – all in real time, of course … It gets pretty darned busy when we're under attack. See those empty desks? I imagine you'll be spending a good deal of time there, Dr Crowe.'

'Samantha. Or Sam.'

'Those systems are our underwater eyes and ears,' Peak continued, as though he hadn't heard. 'Antisub surveillance, SOSUS sonar and Surtass LFA, to name a few. Nothing approaches the Independence without us knowing about it.' Peak pointed at a screen mounted at the head of the room, showing a patchwork of diagrams and charts. 'The big picture. An integrated overview of all the information received by the CIC. A smaller version appears on the screens in the bridge.'

Peak led the way through the adjoining rooms. Almost all were shrouded in half-light, illuminated only by screens, monitors and displays. Next to the CIC was the Landing Force Operations Center. 'It's the command centre for the Marine Expeditionary Units. Each unit has its own console. During a landing operation, satellite images and recon planes are used to detect the position of enemy troops.' There was an unmistakable note of pride in Peak's voice. "The LFOC allows us to shift troops and develop strategies in an instant. The central computer links the commander to his units in a ship-to-shore system.'

Crowe recognised pictures of the flight deck on some of the screens. She knew Peak probably wouldn't appreciate the question, but she couldn't help asking, 'How will that help us, Major? Our enemy's at the bottom of the sea.'

'Sure. So we'll use our capabilities for a deep-sea operation. I don't see the problem.'

'Sorry. I guess that's what comes from spending too much time in space.'

Anawak grinned. So far he hadn't said a word, but Crowe found his presence reassuring. Peak continued the tour. The Joint Intelligence Center came next. 'All the data from the recon systems is decoded and interpreted here,' said Peak. 'If anything gets too close to the Independence, we take a good look at it, and if the boys don't like it, they shoot it down.'

'That's a pretty big responsibility,' murmured Crowe.

'The computer does some of the work for them,' said Peak. 'But you're right, of course.' He gestured towards the other rooms. 'Most of what goes on in the CIC and JIC is pretty technical stuff, but we also keep an eye on the news from all over the world. We've always got CNN and NBC on screen, plus a dozen or so other key channels. You'll have access to all the information you need, including the databases of the Defense Mapping Agency. The navy's maps are far more detailed than anything available in the public domain, and you'll have the privilege of using them.'

They carried on down. After the on-board store came empty dormitories and living-quarters, then the hospital on 03 LEVEL, a vast antiseptic expanse with six hundred beds, six operating theatres and a gigantic intensive-care unit. It was deserted. Crowe imagined the scene during an attack: people screaming, blood flowing, doctors and nurses rushing from bed to bed. The more she saw of the Independence, the more it seemed to resemble a ghost ship – or a ghost city. They began the ascent up to 02 LEVEL and continued aft, until they reached a ramp wide enough for vehicles to drive down.

'The tunnel starts in the bowels of the vessel and zigzags all the way up to the island,' said Peak. 'The layout of the Independence allows all the strategically relevant areas to be accessed by jeep. In an assault situation, the marines would use the tunnel too. Let's head down.'

The steel bulkheads resonated with their footsteps. For a moment Crowe was reminded of a multi-storey car park, but then the enclosed ramp opened on to a hangar bay. Crowe had read that it covered a third of the ship's total length, with a height of two entire decks. There was a strong draught. On either side a colossal open gate led out on to a platform. Pale yellow lighting combined with the sunshine seeping through the gates to bathe the area in hazy light. Glass booths and control points were housed between the ribs. Hooks hung from above, attached to some kind of monorail. Crowe spotted large forklift trucks and two Hummers.

'Usually the hangar bay would be full of aircraft,' said Peak, 'but for this operation we'll only be needing the six Super Stallions that are docked on the roof. In the event of an emergency, we'll be able to evacuate fifty people per craft. We've also got two Super Cobra attack helicopters aboard, in case we need something with a bit more zip.' He pointed to the two gate-like openings. "The external platforms are elevators for transporting aircraft from the hangar bay to the roof. Each deck elevator has a capacity of over thirty tonnes.'

Crowe walked towards the starboard gate. The steely grey sea stretched towards an empty horizon. Few icebergs found their way into these waters. The East Greenland Current transported them along the coast, three hundred kilometres away. The Independence would only encounter occasional patches of slushy drift ice.