Janice took a deep breath and looked at the nurse. She looked dead on her feet. “Okay, we’ll be up there soon,” she said, and closed the door gently.

“Well I guess you’re going to get your way, Surgeon Lieutenant Vardy. It looks as if circumstances are pushing us into live clinical trials here, whether we’re ready or not.”

“It’s the right thing, Janice. Trust me, it will be fine. Look, let’s get another batch into the machine before we go. We need this thing running twenty-four seven making antiviral.”

• • •

There was a final door for Jake to try. He had reached the end of the tunnel. Of course, he hadn’t explored fully in the other direction, but his rapidly deteriorating condition suggested he never would. Not without some kind of miracle or medication, anyway.

The last door was different to the others. For one thing, it wasn’t set into the side of the tunnel wall. It was head-on, facing him as he reached the end. For another thing, this door was much wider; the full width of the tunnel. This was an entry or exit that was designed for passing heavy equipment, or a lot of people in one go.

There was no simple handle to open it. Indeed there was not, at first glance, any visible means of opening it at all. Jake studied it for a while. He felt very dizzy. His new set of wheels had got him further and faster than he’d managed before, but his energy level was at an all-time low nonetheless. He could feel his body using all of its resources to try and fight off the virus. The battle going on inside was also creating heat, a lot of heat, and the wetsuit provided no ventilation, which just made matters worse. The team had brought bottles of water with them, but those had been left in the crate on level three. Nobody had thought, in the heat of the moment, to leave anything for Jake. He could almost have killed for a swig of ice-cold water. His mind wandered, thinking about how sweet it would taste, how cooling it would be as it trickled down his throat. The trickle of water turned into a cascade, and he found himself standing under a waterfall. The cold water pounding against his skin felt incredible, refreshing, revitalising. He looked up and saw a bright blue sky, dotted with tiny white clouds. Someone was near him, splashing around in the water with him. Was it Lucya? He tried to move, to get closer and take a look.

With a bump and a clang, he landed on the grated floor. He had lost his balance during the daydream. His head hurt, but he couldn’t tell whether it was from landing on it, or the virus attacking him.

For the first time, he considered giving up, right there. He told himself that the virus would kill them all soon anyway, that he was lucky. He would get to die peacefully in this place rather than in the chaos of a ship full of sick people all demanding attention.

And yet somewhere, deep inside him, a flame of hope still burned. Hope, and faith. Not a religious faith: that was something he’d never had. Rather, a faith in Doctor Russell Vardy. A faith in Doctor Janice Hanson, a faith in Lucya, Martin, Coote, and the rest of the crews of the Spirit of Arcadia and of HMS Ambush. There was still time. They had the machine. They could still make it. Giving up now would be to give up on them, and he knew they deserved better. He owed it to them to stay alive. They were working with every ounce of effort they could muster to save him, and all the others who had been infected. The least he could do was stay around to be saved.

With renewed motivation, he forced his eyes open and tried to push himself back up into a sitting position.

It was then that he first noticed the panel in the wall. He hadn’t seen it before, because he had been focussed on the door itself. The panel was on the right-hand wall, set a metre or so back from the door. Its purpose was in no doubt, because stencilled large in bright yellow paint, was a notice. It said simply: “Push to Open.”

The panel was, of course, out of his reach. But not by much.

Jake had left his torch back in the generator room, but he still had his gas mask. Sitting as upright as he could, he held it by one of its two filters and tapped the panel with the other.

Nothing happened at all.

He tried again, tapping harder. The panel moved, although barely, recessing itself further into the wall. But still, nothing. It was as if it wanted to be pressed by a hand rather than an inanimate object.

Jake remembered the trolley. It was right behind him. He pushed it around so it was pressed against the opposite wall, and heaved himself back on board. Getting it turned round again was more of an effort, but he was a determined man and after a couple of false starts he found himself sitting next to the panel, just high enough to be able to reach it. He raised his hand, placed it in the centre of the rectangle, and pushed.

It looked like nothing was going to happen again, but then, from somewhere inside the wall, a deep rumbling sound emerged. In front of him, the huge door started moving, sliding upwards, right into the ceiling.

• • •

Had Kiera Stevens been in a better state, she might have objected to the audience gathered around her bed. Surgeon Lieutenant Russell Vardy, Doctor Janice Hanson, three nurses, including Mandy, who had been awoken from her delicious slumber by the commotion, and Lucya. They were all packed into the small stateroom in which Kiera and Barry had been laid up. As it was, Kiera was entirely oblivious to those watching on; she had long since lost consciousness. That was a blessed relief for her, because she was decaying fast. The nurse had not been wrong with her diagnosis. Kiera did not have much longer to live.

Vardy was trying to administer the antiviral, but it was not proving to be easy. Although Kiera was unconscious, her limbs were twitching, almost convulsing. It was as if the virus knew it was about to be attacked and had taken possession of her, making it nigh on impossible for the surgeon lieutenant to inject the drug. Even when he was able to grab an arm or a leg briefly, before it was snatched away by another involuntary muscular movement, he was having great trouble finding a vein. Her skin was covered in red blotches, some so deep they had become black. In places, the flesh was falling away completely.

“Doctor Hanson, I’m going to need some help here,” he said, frustration raising the pitch of his voice. “You need to hold down her arm long enough that I can get this in.”

Janice stepped forward. During her career as a forensic pathologist she had seen bodies that were in a terrible state. Burnt bodies, crushed bodies, decapitated bodies, even brutally beaten and half-eaten bodies. But every one of those bodies had had one thing in common: they had all been dead.

Kiera was a whole different matter. Her consciousness may have left her long ago, but the convulsions made it clear that this was a body very much still alive. Seeing a living human being in such a dreadful, awful state was almost more than she could bear.

Janice pulled the straps of her surgical mask tight, which helped to block the worst of the smell. She checked her latex gloves were on, and after a moment’s hesitation, made a grab for the arm. Kiera gave a moan, but Janice had got it, and she wasn’t letting go.

“Excellent,” Vardy said. “Try and keep it pinned down, and twist it a little away from me, so I have more chance of finding the vein.”

Janice did as she was asked, pushing the limb down onto the bed. Gripping the forearm with both hands, she rotated it carefully towards the two of them. There was a sound like an apricot being twisted open. Janice’s stomach turned as she felt Kiera’s flesh detach from the bone inside. She exclaimed, and dropped the arm, shaking her own hands as if they had somehow been soiled by the ripping flesh.