Fifteen minutes later, Sean scaled the slatted wooden fence at the end of the rear garden of a small semi-detached house in Cochron Road and dropped silently onto the overgrown lawn. There was a light on in the kitchen. Three men sat round a table drinking beer from cans and smoking cigarettes, but there was no sign of Angela or Niamh.

As Sean edged closer to the rear of the house he recognised them. Chip O'Shea: a ratty little prick with rotting teeth and a permanent sneer. Marky-Mark McGuigan, who rode shotgun for O'Brien and the big man himself, sitting at the head of the table scowling at the hand of poker Chip had just dealt him. He was positioned at the far end of the kitchen closest to the door and was partially obscured by the other two.

Sean hadn't seen any of them for almost ten years, but aside from slightly heavier-set faces and less hair they all looked exactly the same.

He had a clear line of fire to McGuigan and O'Shea, but O'Brien was more difficult.

There was no clear plan. All Sean had to do was wait for something to happen: that's what Danny had said as the two had parted company.

He didn't have to wait long. Suddenly all three men stood up. O'Brien reached behind his back and pulled a handgun from his belt. The skinny guy, O' Shea, picked up an Armalite from underneath the table and was already on his way out of the room with Marky-Mark following close behind, a shotgun clamped across his chest.

Sean raised the assault rifle to his shoulder and took aim.

On the other side of the building, outside the front door, stood Danny with his finger on the doorbell. He wasn't going to release it until someone answered.

In his left hand he held a Heckler & Koch P7 with a suppressor fitted: the small round end of which was pressed firmly against the spyhole situated two-thirds of the way up the door.

He heard a voice from inside. 'Who is it?' asked Chip O'Shea.

'The bogey man,' replied Danny.

Danny counted three seconds for Chip to put his eye up to the door and fired a single shot through the spyhole.

From the far end of the hall Owen O'Brien saw a jet of blood spraying out of the back of Chip O'Shea's head before his skinny frame slumped slightly and collapsed limply to the floor.

Outside in the garden Sean squeezed off two short bursts. The kitchen window shattered and O'Brien saw Marky-Mark's body suddenly lift three or four inches off the ground and fly backwards against the kitchen wall. Half of his face was missing and there was a stream of blood pumping steadily from a cluster of bullet holes in the middle of his chest.

There was a loud rapping noise next to O'Brien and a cluster of ragged holes suddenly appeared in the door frame just above his right shoulder. Splinters of sharp wood lacerated the side of his face. He lurched to the side and tumbled out of the kitchen.

O'Brien's instinct was to run. He considered heading out through the garage, but there was no way of knowing who, or how many, were involved in the attack: it was too risky. His best option was to get the girl.

The garden was now in total darkness. Sean was sure he'd taken down Marky-Mark with his first burst of fire, but he couldn't be sure if he'd been killed outright. He made his way over to the kitchen window and climbed onto a waste pipe. Marky-Mark's body lay still on the kitchen floor.

Sean hauled himself onto the ledge and swung his legs over the sink, then dropped onto the linoleum-covered floor. As he cleared the doorway he saw O'Shea's body lying at the other end of the hall.

Suddenly there was movement upstairs and the sound of a young girl screaming. Outside Danny could hear the screams too. He stood back and emptied a full clip into the front door, then started kicking.

Sean made his way quickly down the hall. 'Wait up, Danny, wait up, it's me, I'm inside,' he said with an urgent whisper.

Sean bent down, dragged Chip O'Shea's limp torso clear of the door and yanked it open. There were a few more muffled screams then the house fell silent. Danny dropped the clip out of the bottom of his gun and reloaded. 'You keep me covered till I get to the landing, then I'll cover you,' said Danny.

Sean knew what his brother was doing. The first person onto the stairs was the most likely to get shot. Danny was volunteering to be that person.

Sean shook his head. 'I'm going first.'

Before Danny had a chance to argue, Sean was already at the foot of the stairs. With his AR15 pressed firmly to his shoulder Sean cautiously made his way up to the first landing. After checking that there was no one on the floor above, he gestured to Danny to join him. Sean then edged up the next flight of stairs until he was standing outside the door of a bedroom on the upper landing. There were two other doors leading off: all of them closed. Sean tried the first handle. It wasn't locked.

Danny was squatting on the step just below him, with his back against the banister his gun pointed at the bedroom door. When he gave the nod, Sean twisted the handle and pushed. The door swung open and crashed noisily against the wall inside the room.

The men stood stock-still and waited, listening.

An uneasy silence returned to the house. Sean moved first, slipping sideways into the darkened room. The stench of urine, dried faeces and vomit was overwhelming. He immediately put his hand up to cover his mouth and nose. Danny was right behind him, standing in the doorway, peering into the gloom: unaware that this was where Angela had been just a few days earlier. The windows were boarded up and all the furniture had been removed except for a single solitary chair that sat in the middle of the floor. Sean knew instantly what the room was used for. If he'd learned anything from his years away it was that he no longer wanted anything to do with this life. If he survived the next few days, he was getting out and never coming back.

A muffled thumping noise from overhead made them both turn back to the hallway. The hatch leading to the attic was open: the hole cut in the ceiling was much larger then normal.

'O'Brien's trying to get next door through the roof space,' said Danny, as he climbed onto the banister and tried to hoist himself up into the dark void.

There was a sudden flash of light from somewhere deep inside the attic and the wooden rafter just above Danny's head made a loud cracking noise as a bullet from O'Brien's gun burst through it. Danny ducked out of the line of fire, but lost his footing on the banister and fell heavily onto the floor of the landing.

Sean quickly pulled him up. 'You okay?'

'Fine,' replied Danny. 'O'Brien's in the roof space of the other house.'

'I'll head out the front and see if I can get in next door,' said Sean, already on the move. 'You stay here in case he doubles back.'

But Danny had no intention of staying anywhere: he was already balancing on the banister, reaching up to try again. He grabbed hold of the ceiling joists that ran along the inside of the trapdoor and heaved himself up into the darkness.

O'Brien had wrapped some tape round the girl's mouth to try and shut her up, but she was still hysterical, writhing around, making it difficult to move quickly. It would be much easier just to shoot the little bitch in the head. He considered it for a second, but right now she was more valuable alive. Once he was clear of the house he'd rethink.

The IRA owned both properties and had knocked through the dividing wall in the attic to provide an escape route in case the security forces raided either of the houses. But some arsehole had padlocked the attic door in the other house shut. O'Brien stamped down heavily on the flimsy hardboard panel with his foot, but it didn't budge.

There was a movement to his right. He glanced over and saw Danny McGuire's head poking through the open hatch in the roof space next door. O'Brien fired one round, but it was impossible to tell if he'd hit him or not. Two more shots at the metal plate that secured the padlock in place, and the trapdoor dropped open.

He only had one full clip twelve bullets in total after that he was out. The rest of his shots had to count.

The first-floor landing next door was in darkness and the air smelled damp and fusty. Moments later O'Brien was climbing down the foldaway ladders with Niamh slumped over his shoulder like a rag doll.

Just as he reached the head of the stairs, there was a burst of automatic gunfire and the front door flew open. He pulled Niamh round in front of him and pressed his gun roughly into her temple. She flinched and started struggling again, but he simply squeezed more tightly, crushing the air out of her until she stopped.

O'Brien had nowhere to go, but that didn't matter. He had the girl.

He glanced quickly from side to side; first at the hatch in the ceiling, then down to the hallway below. He was pumped: ready for anything. 'Life or death: who gives a fuck?' he thought.

A narrow opening in the middle of the brick wall was all that separated the two buildings. There were three large white box-shaped objects sitting in a row under the ridge of the roof. Danny made his way carefully over the ceiling joists towards the crude doorway. As he got closer he realised that what he thought were boxes were actually large larder freezers. This explained why the trapdoor to the attic was much wider than normal. It must have been enlarged to accommodate their bulk. It was a curious thing to do: who would want such large freezers in their attic? He edged his way over and lifted the lid of the one nearest to him. As it opened, the freezer light came on, illuminating the surrounding attic space with a dull eerie glow.

The sight that greeted Danny as he peered inside made his stomach turn. The freezer was full of body parts. Laid up like lumps of meat: butchered to make them fit the confined space. Stored here to prevent them from spoiling and causing a stench, until such time as they could be disposed of more permanently. A piece of arm cut from the elbow joint was clearly visible through a thin layer of white frost. But worst of all, a head shorn at the neck: the face partially covered by long matted strips of hair and caked with dried blood; the drawn, colourless skin stretched tight over its skull.

Danny stared at the head in horror, unable to break away. Suddenly every muscle in his body contracted in the same instant, as a terrible realisation left him struggling to catch his breath.

He recognised the face.

Danny reeled back, slamming the lid closed behind him, and crawled backwards until he hit a wall, forcing him to stop. Why had he opened the lid? What had made him do it?

He started to retch.

Danny could hear voices from next door and Sean calling out his name, but he couldn't answer.

The image of the raven battling for its life in the Black Warrior River flashed through Danny's mind, and he wondered if that was the moment Angela had died.

It had been an omen not for Sean, but for his Angel.

He'd broken his promise to take care of her.

As Sean made his way along the hallway O'Brien appeared on the landing at the top of the first flight of stairs with Niamh clamped to his chest and a gun digging into her temple.

'Leave the girl be, O'Brien, she's got nothing to do with this,' said Sean.

He was weighing up the possibility of taking a shot. But Niamh was covering most of O'Brien's torso and she was moving around too much: it would be far too risky.

'A dead man talking: that's quite an act you've got, Sean,' said O'Brien. 'I bet you're wishing you'd stayed dead now, eh?'

'Being a tout not enough for you any more, Owen, you have to abduct wee girls as well?'

'Shut your mouth and drop your weapon on the floor.'

Sean knew that if he didn't do what he was told then O'Brien would simply pull the trigger and Niamh would be dead. If he did do what O'Brien asked him, then Danny would be the only hope left of getting out alive.

'Drop it on the floor and kick it towards me,' repeated O'Brien.

Sean had no choice. He bent forward and tossed the AR15 on the floor out of reach.

'Tell your brother to throw his weapon down and come out of the attic with his hands where I can see them.'

Sean was out of options. While O'Brien had the girl there was nothing he or Danny could do, but as soon as his brother gave up his weapon O'Brien would shoot them all and walk away: of that, there was no doubt.

Sean shouted to his brother, but there was no reply.

He tried again.

'Danny!'

O'Brien had his eyes fixed on the opening in the ceiling at the far end of the hall.

'I want you down out of that attic in ten seconds or I'm going to put a big fucking hole in this wee girl's head,' shouted O'Brien. 'Drop your gun onto the floor and get your arse down here. No fucking about now, all right?'

When O'Brien looked back at Sean he saw that he had taken a step closer to the bottom of the stairs. 'Got a notion to rush me, big fella?'

O'Brien fired a single shot that hit Sean on the bottom of his thigh, just above his knee. The force of the impact made his leg buckle underneath him and Sean dropped to the floor.

"I'm not fucking around, Danny,' continued O'Brien. 'Out of the attic now or I'll kill the two of them. Your brother's already down. You've got ten seconds before I shoot again, only this time I'll be aiming for his fucking skull.'

O'Brien started counting.

'Ten . . . nine . . . eight . . . seven . . .'

When he got to 'three' there was a hard metallic sound as Danny's gun clattered down the attic steps and onto the floor.

A few seconds later Danny emerged from the hatch and slowly made his way down the ladders, until he was standing less than three yards from O'Brien with his hands hanging loosely by his side.

Niamh started writhing around, but once again O'Brien tightened his grip and squeezed her until she could no longer move.

Danny could see the fear in his young niece's eyes. 'Don't you worry about a thing darlin, okay? Everything is going to be all right,' he said, trying to reassure her.

'Yeah, don't you worry there darlin,' repeated O'Brien. 'Everything is fucking great. You'll all be together, very soon. Might be a bit cold for you, but don't you worry darlin, okay!'

Danny knew exactly what O'Brien was referring to, but he wasn't going to give him the satisfaction of acknowledging it. His face betrayed no emotion.

The sound of Sean's laboured breathing could be heard coming from downstairs.

'You okay, Sean?' shouted Danny.

'Fine,' came the reply. 'Copped one in the leg, but I'm fine.'

Danny looked straight at Niamh. 'Do you remember the trick I taught you when we used to do our dummy fighting?'

Niamh looked puzzled for a second, then gave a slight nod.

'Shut your mouth, McGuire,' said O'Brien, sensing that Danny was up to something.

'You have been found guilty of treason against the republican cause and sentenced to death,' continued Danny, shifting his gaze from Niamh to O'Brien. 'I'm here to carry out the will of the Republican Army council and execute you.'

O'Brien stared back in disbelief. 'And people think I'm off my fucking nut. You take the biscuit, big fella. You're not even a fucking member of the RA.'

'I was given a job to do and I'm here to do it,' replied Danny. 'Let the girl go,' he said, keeping his tone steady and resolute.

'Maybe you hadn't noticed, fuckwit. I'm the one with the gun,' replied O'Brien. 'Look,' he said, relishing the moment as he pointed the pistol downstairs and fired another round into Sean.

Danny heard an agonised groan from Sean as the bullet tore a strip of flesh from his arm.

'You're fucked, Danny boy. Once I've killed your brother, and shot this wee girl in the head, I'm going to kill you. Then it's off to the pub for a pint. I don't know what I'm looking forward to the most: watching your face as I kill them, or watching your face as you die. Or will it be the look on people's faces when I tell them that you were the Thevshi all along? I'll tell them you squealed like a stuck pig when you realised you'd been found out. What a result! O'Leary is going to lap this up like a cur at a desert well. It's been fucking with his mind for years who "The Ghost" could be. Too easy, shitehawk, too easy! Couldn't have worked out better if I'd planned it myself.'

'O'Leary's dead,' said Danny.

O'Brien hesitated momentarily, a brief flash of doubt crossing his eyes. 'Aye right?'