Wedged in the crook of a tree eighty yards away, the sniper watched through his high-magnification scope as Arno’s body dropped out of view. With his gloved thumb he quickly flipped the select fire toggle from single shot to fully automatic and fired a long burst through the study windows. Glass shards and chunks of stonework flew as the bullets struck. He smiled.

Ben had hurled himself over Arno’s desk, grabbed Leigh’s wrist and dragged her to the floor. He ripped the disk out of the computer. The screen was smoking from a bullet-hole.

Another burst of gunfire shattered the rest of the window. It chewed a line of ragged holes in the top of the desk, blew the computer apart, and strafed the book cabinet at the far end of the study. The silver candle-holder toppled over as the decanter of grappa shattered. The strong drink burst into flame, liquid fire pouring onto the carpet where it quickly caught a hold.

Ben and Leigh pressed their bodies tightly against the thick wall beneath the window, a storm of splinters and glass around them. Ben drew the.45 from his belt and fired blindly through the broken panes.

He could smell burning. He twisted round to see where it was coming from. Black smoke was filling the far end of the room. Fire was crackling up the length of the door-frame.

Arno lay slumped under the desk, blood spreading across the rug. Leigh crawled over to him. His eyes were glazing over. She wanted to do something, stop the bleeding, move him away from the window. There were so many more things she wanted to know from him. ‘Professor, the letter,’ she said frantically. ‘Where’s the letter?’

The old man’s eyes focused on her for a second. His lips moved almost inaudibly, trickling bloody froth.

The shooting outside had stopped. Ben peered out of the shattered window. He couldn’t see anyone, but there were voices and running footsteps down below in the courtyard. The crackle of a radio.

Half the room was on fire now. The bullet-torn books in the bookcases burst alight. The smoke was thickening fast.

Arno coughed, and bright blood appeared on his lips. He tried to speak. Then a long sigh whistled from his lips and his head slumped to the side.

Ben glanced at him. ‘He’s dead, Leigh.’

Leigh was shaking the old man. ‘He was trying to say something.’

‘There’s nothing you can do for him. Let’s move.’ Through the ringing in his ears and the crackle of the fire he could hear the sound of movement downstairs. They were coming. He checked the gun. Three rounds left.

Fire blocked the doorway. They were going to have to run through the flames. He grabbed the dead man’s jacket from the stand. He pulled Leigh to her feet and draped the heavy tweed over her head and shoulders. Keeping hold of her arm he took two fast steps into the choking smoke and kicked hard. Flame licked his ankle. The study door juddered open. He shielded his eyes and ran through the fire, pulling her through behind him.

The corridor outside was empty. Footsteps thumped on the stairs. Ben ran to the right, gripping Leigh’s arm. Through a doorway at the end of the corridor there was a short flight of steps and then another door. Ben had a rough idea where he was. On his way in he’d noticed the square clock tower rising up from the centre of the house, with shuttered windows on each side overlooking the sloping roofs. He wrenched open the door. He was right.

The winding stair took them upwards. The door to the tower was thick old oak. They ran inside and Ben barred the heavy door with a wooden beam. He looked around him, getting his bearings. Voices. Someone was thumping at the door. Leigh jumped as shots went off.

‘This way.’ Ben nodded towards the shuttered windows on the next level. The wooden stairway was old and rickety. He guided her up ahead of him.

Down below, the blast of a shotgun boomed through the tower and splinters flew from the inside of the old door. They’d be through it soon.

Ben kicked open the shutters and they were looking out across the broad expanse of red-tiled roof. Dusk was falling.

Leigh could feel her legs shaking as she clambered out of the window and onto the roof. The height made her dizzy. Ben guided her along the red-tiled ridge. She kept her eyes pinned to the wooded horizon and the falling sun.

The roof sloped down to the side. He steered her that way, taking them lower. She slipped on the weathered clay tiles and almost fell, but his grip on her arm was firm. He peered over the edge. They were still a long way from the ground.

The tower window shutter burst open and a man appeared. He was wearing a black jacket and holding a stubby machine pistol. Its muzzle flashed and bullets whined off the tiles near their feet. Ben returned fire. The man fell back against the tower.

Ben shoved the pistol in his belt and took Leigh’s hand. ‘Trust me,’ he said, reading the look in her eyes.

Then he took two steps to the edge of the roof and leapt into space, taking her with him.

Leigh gasped as they fell. Then the striped canvas canopy was rushing up to meet her, knocking the wind out of her, and they were sliding down it. There was a crack as the flimsy aluminium frame holding the patio awning to the wall gave way. The taut canvas enveloped their struggling bodies and slowly, gracefully, collapsed in an arc to the outdoor eating area below.

Ben crashed down against a brick barbecue, and Leigh had a softer landing into a circular plastic table. She rolled off it and landed on her hands and knees on the ground, only a little scuffed. Ben staggered to his feet, clutching his back and grimacing in pain. He grabbed her hand again.

They ran through the gardens. Over the rasping of her breath Leigh heard shouts behind. Some shots rang out and Ben felt a bullet pass close by. They scrambled through dense shrubs and found themselves in wooded parkland. They sprinted on through the trees, branches whipping at their faces. Up ahead, a high stone wall had crumbled to leave a gap they could clamber over.

On the other side of the wall was an old farmyard, overgrown and muddy, dilapidated wooden buildings streaked with green lichen. Ben looked back through the gap in the wall. There were six men running fast towards them. Their faces were hard and determined and they were heavily armed.

His pistol only had two rounds left. He took aim, then changed his mind. He could kill two at most, and he’d be left with an empty gun. A fatal tactical error.

They ducked into an old shed. The rotting building was filled with shelves and boxes and tools. Ben snatched up a rake and tried to wedge the door with it, but a heavy body crashed into the door and knocked it open. Ben kicked it shut. The man’s arm was trapped in the door. He had a Skorpion machine-pistol in his fist. Deafening gunfire strafed the inside of the shed. Leigh screamed.

Ben grabbed a rusty tool from a nearby shelf. It was an air-powered nail-gun. He pressed it hard up against the man’s thrashing arm and squeezed. With a bang, the arm was pinned to the door-frame with a rusty four-inch nail. Blood spurted. Ben fired three more nails into the howling man’s hand and the Skorpion clattered to the ground. He picked it up. Empty. Useless. He threw it down.

Bullets tore through the shed’s thin wooden walls. A pile of crates collapsed and revealed a gap in the planking that was big enough to squeeze through. They ran on across a muddy passage and slipped inside a barn opposite.

The gunmen saw the barn door swing shut and approached the tall wooden building cautiously, exchanging wary looks, their weapons trained. There was a heavy silence in the farmyard, just the sound of two crows calling in the distance.

Then the sudden sound of an engine revving hard. It was coming from inside the barn.