Sampson scuttled over to the door, s.n.a.t.c.hing a look outside, at the same time picking up the gun from the dead guard.

Three guards lay dead in the hallway between this room and the front door, and through the front door, Sampson could see the police advancing.

I'm the only one left, he thought, and along with the excitement came another new feeling: fear. He was outnumbered, outgunned. There was no way he could win. He thought about Kate downstairs. If he died now, he would never see her again.

He tried to work out what that meant. Why did it make him go cold inside?

A black-clad police gunman appeared in the doorway and, instinctively, Sampson raised his gun and shot him. The policeman dropped to the ground and Sampson heard yells from outside. Bullets crashed into the walls and the doorframe.

He could stay here, hold the police up. Try to protect Gaunt for longer. He might take out one or two more policemen. It would give more time for the boy to spread the virus.

But he didn't care about that. He never had.

He crawled back across the floor to the stairway, pausing to throw the gun he had taken from the dead guard to the whimpering Asian scientist. This wasn't an act of kindness. He knew that if the police saw the scientist with a gun they would shoot him too.

Sampson also knew what he wanted. He was going to take Kate with him. All the way to h.e.l.l.

In the lab, Gaunt was pressed against the gla.s.s, desperate to know what was going on.

Behind him, Paul said, 'You're not so brave without your bodyguard, are you, Gaunt?'

'Shut up.' He tried to sound in command but his voice cracked.

Paul walked up to him and grabbed him by the throat, pushing him up against the gla.s.s. 'I really, really feel like killing you, Gaunt. For what you've done to Stephen. For giving Jack the virus. I should kill you right now.' He squeezed, pressing his hand hard against Gaunt's windpipe. Gaunt made a pathetic, strangled noise.

'Where's the anti-virus?' Kate asked, standing at Paul's shoulder.

Gaunt tried to shake his head.

'The Pandora anti-virus. Where is it?'

Paul loosened his grip on Gaunt's throat so he could speak. 'I'll never tell you.'

Kate said, 'It has to be here, in one of these freezer units. We'll find it. We might have to search through every one, but...' she knew this would be a difficult task, but she didn't want Gaunt to think his life was valuable to them.

'I don't care if you kill me,' Gaunt said. 'I'm not going to tell you.' But Kate saw his eyes widen with horror, and she turned to see what he was looking at.

Stephen had opened one of the freezer units. A cloud of cold steam wafted out as he slid open a drawer. He had pulled on a pair of gloves, and he took out several vials and held them out on his palm towards Kate.

She smiled, while Gaunt made a gasping noise behind them.

'It doesn't matter,' he said. 'It's too late.'

'Definitely too late for you,' Paul said, increasing the pressure on Gaunt's throat. 'Tell us how to get out of this lab.'

'There is no way out without the card.'

'There must be. You built this place. You must know.'

'There isn't any way out!'

'It doesn't matter anyway,' Kate said. 'The police will be down here in a...'

Her words were cut short by the sight of Sampson appearing at the end of the hallway and running towards the lab.

Sampson punched in the code and pulled the door open, keeping it propped open with one foot. In one swift motion, Paul shoved Gaunt further back into the room, grabbed Kate's hand and charged at Sampson in the doorway, barging past him Paul and Kate stumbled into the hallway, knocking Sampson to one side, and the lab door swung shut, leaving Gaunt and Stephen inside.

Gaunt banged on the gla.s.s but n.o.body took any notice of him. Paul aimed a punch at Sampson, but the larger man blocked it and threw a punch back, cracking Paul's nose and sending him crashing to the floor, clutching his face, blood pouring into his palms.

'Run,' he said to Kate through the blood, and she obeyed, sprinting up the corridor towards the doorway, knowing that the police, and safety, were upstairs.

Sampson raised the gun and aimed it between Kate's shoulder blades.

In the lab, Gaunt continued to thump the gla.s.s, screaming for Sampson to let him out. He was so busy demanding his release that he didn't notice Stephen opening the doors of the storage freezers behind him. Methodically, Stephen opened drawers and took out vial after vial, collecting them together on the bench.

The finest pieces in Gaunt's virus collection lay side by side. Marburg. Spanish Flu. SARS. Avian Flu. Watoto. Pandora.

And another virus, one that Stephen had worked on a couple of years before. It was code-named Piranha and was a kind of super-charged Ebola, attacking the body at breathtaking speed, melting the insides within minutes, causing haemorrhaging from every internal organ and an agonising death. Gaunt had abandoned research on Piranha because it kept killing lab a.s.sistants. It was simply too dangerous to work with, and would have been impossible to spread effectively into the world.

Stephen picked up the test tube containing Piranha and walked calmly across the lab, tapping Gaunt on the shoulder.

Gaunt turned around and Stephen smashed the vial in his face.

In the second before she reached the door, Kate looked over her shoulder. Sampson was pointing the gun at her. His face was contorted with pain, and even in that moment she registered the strangeness of seeing emotion on Sampson's face.

She threw herself at the door, fully expecting that at any moment she would feel the hot burn of the bullet. She would never see Jack again, never be able to save him.

But the bullet never came.

She crashed through the door into the stairway, almost hyperventilating, ran up the stairs two at a time, stopping short when she heard a gasp above her.

The Asian scientist, whose name was Keiji Utada, was standing at the top of the stairs, a gun in his hand. He was shaking, looking at the door, then at her. She stopped. From the other side of the door she could hear the police ordering Utada to let them through.

Utada pointed the gun at her, then let his arm drop. He was drenched with sweat and looked like he would collapse at any second.

'Give me the gun,' Kate said firmly, holding out her hand as she reached Utada. He hesitated, not knowing what to do. The police were banging on the door. Utada slumped, releasing the gun, and Kate scooped it up, just as Sampson appeared below her.

He raised his gun. Kate raised hers. Her hands shook; she had never used a gun before. She tried to aim, but she was trembling too much. Sampson slowly ascended the stairs, his gun still trained on her.

He stopped a few steps below her. Kate was still trembling, trying to aim, tears of terror filling her eyes. All Sampson had to do was squeeze the trigger but he didn't.

The police burst through the door just as Kate dropped to her knees, the gun clattering down the stairs. The last thing she saw before she blacked out was Sampson raising his arm to take aim at the police gunmen behind her. The last thing she heard was a burst of gunfire that blew Sampson down the stairs.

CHAPTER 46.

Agent Jason Harley realized that he was going to have to physically prise Paul away from the locked door of the laboratory, where he had been repeatedly beating his fists against its thick steel surface.

'Stephen! Stevie! Stephen!' Paul cried, over and over again, tears flooding down his face. He was clearly either totally unconcerned for his own safety, or oblivious to the frenzied gun battles which had just taken place on the stairs not twenty feet away.

'Stevie, mate, come on, open up! We can fix it, we'll get you out of here, it's not too late!'

Harley had heard Paul's shouts from the top of the stairs; heard the raw emotion in his cracked voice; knew that Paul realized the impossibility of what he was saying.

He risked a glimpse through the porthole window of the lab door, and looked hastily away again, sickened to his stomach at the carnage inside: the two still-writhing bodies on the floor, thick black blood spread in a sea around them, obscuring what was left of their features.

Harley hadn't expected Operation Castle to end like this. He'd expected to find women kept prisoner, or at least the evidence of them. Not a locked laboratory with two bodies inside it, including the body of one of the men they'd come to arrest.

What the h.e.l.l had happened here?

'We've got to help him!' Paul sobbed. 'He's my twin... he's been locked in here for fifteen years... I had one chance to get him, and I f.u.c.ked it up! Now I've lost him all over again...'

One of the armed police officers approached Harley and spoke softly to him. Then his colleague, Simon Donahoe, came jogging down the stairs, panic evident on his face.

'Have you got any idea what's been going on here?' Harley asked.

Donahoe nodded. 'I've just been talking to Kate Maddox. You're not going to like this. We need to get out of here. And keep that lab sealed.'

'Why, what's the story? We come here thinking we're going to find women who've been kidnapped and trafficked and instead it's like the frigging Andromeda Strain.'

Donahoe looked at Harley blankly then moved over to Paul, taking him by the arm. 'Sir. We need to get you out of here now.' He turned back to Harley. 'I'll explain everything when we get upstairs.' Paul leaned his forehead on the cool steel door, exhausted. He suddenly straightened up. 'Kate where's Kate?'

Donahoe put a hand on Paul's shoulder. 'She's fine, sir. She's upstairs in the car. We need you to come with us back to London so we can...'

Paul interrupted. 'No! I'm coming with Kate.'

Harley sighed. 'I'm sorry, pal, but I don't think you're in any fit state '

Paul grabbed him, wild-eyed and tear-stained. 'I'm fine. She needs me I'll be strong for her, I promise. I've let Stephen down, I'm not going to do the same to Kate. Come on, let's go time's running out. We've got to get to Jack.'

Harley shook his head, suddenly feeling very tired, and wondering what kind of situation they were dealing with here. And whether heads namely his were going to roll.

But his sympathies were directed towards Paul when he saw the expression of grief on his face. That was his brother in there? Poor sod, he thought, as they made their way gingerly up the stairs, stepping over the bullet-ridden bodies of Sampson, Utada and the security guards.

Kate was sitting with a female agent called Susan French in the back of a squad car, rocking back and forth, pulling at her own hair. When she saw Paul and the two MI5 agents emerge from the house, she flung herself out of the car and into Paul's arms.

'Paul, oh G.o.d, Paul, are you OK? Thank G.o.d you're safe! Did you get Stephen? It was all such chaos, I ....' She tailed off, at the sight of Paul's face.

For a moment Harley thought that Paul was about to break down again, and he sighed, with mingled pity and irritation. His patience had just snapped. He wanted to know what was going on. Now.

'Talk to me,' he said to Donahoe.

But Kate interrupted. 'We have to get to Jack.' Her voice was high-pitched with hysteria.

'Who's Jack? And why is he so important?'

'Jack's her son,' said Donahoe. 'Six years old. We need to get to him because he's got a virus.'

He told Harley what Kate had already told him, in a barely-coherent babble, when they'd pulled her out of the building. Donahoe and French had also since quizzed Kate and she'd managed to explain about how Sampson had s.n.a.t.c.hed Jack, and then handed him back in Mayfield, complete with deadly cargo.

Harley swore.

'Apparently it makes swine flu and SARS look like a mild dose of hay fever.'

'Wait a minute,' said Paul. 'Isn't that why you're here? Because of the Pandora virus?'

'No, we're here because...' Harley hesitated, unsure of how much to tell them. 'Did you see any young women down there?'

'Young women? What are you talking about?'

Donahoe spoke up. 'This is the climax of an operation investigating people trafficking. For the last six months, young women have been coming into the country from the Far East and Eastern Europe then disappearing. Prost.i.tutes too. We've been trying to find where they were going...and the trail led here.'

'That must be what they used the rooms for, the ones with the bunks,' Paul said, almost to himself.

Kate half-screamed. 'What about Jack?'

'Okay, miss,' said Harley in his practised soothing voice. 'Calm down.'

'No, I won't f.u.c.king calm down. My son has a virus that will not only kill him if we don't get to him but start a chain reaction that could wipe out half the world. Especially if my idiot husband takes him on a plane to Boston.' She had a sudden clear image of Jack at the departure gate, contagious after the safe period had run out, inadvertently pa.s.sing the virus to pa.s.sers-by of every nationality. And all those people would get on their separate planes and head off around the world, taking Pandora home.

'Relax, Miss Maddox,' Donahoe began.

'Doctor Maddox,' she said automatically.

'Sorry. Doctor Maddox. As soon as you told me about this before we put out an APB on Mr. Maddox and your son. We're watching all the approaches to the airports. We know where they're going. We'll apprehend them.'

'What's the latest?' Donahoe asked Susan French, who had just been talking into a mobile.

'Nothing. No Vernon or Jack Maddox booked on any flight out of any airport, nor have they turned up at any port, or Eurostar. No sign of anyone meeting their description. They've vanished.'

Harley groaned. 'f.u.c.k. And this virus has a safe period? We've got how long?'

French looked at her watch. 'The little boy's safe period will expire inriod willtwo hours.'

Kate wailed out loud; half-wail, half-scream. 'Do something! We have to find him!'

'Right,' Harley said. This was what he was best at. Taking charge. Fixing problems. His mind whirred. 'They're clearly not trying to leave the country. Therefore they can't be more than a couple of hundred miles away, at most. Does Maddox have any friends he might have taken refuge with?'

Kate shook her head. 'He doesn't know anyone in England, to my knowledge, apart from my sister, and I doubt he'd have gone back there.'

'No, he hasn't we've already checked that. Your sister is still giving her statement at Oxford police station. Can you think of anywhere at all he might have taken Jack to? A particular hotel? A B&B you once stayed at?'

Clutching at straws here, Harley, he thought to himself.