Jason heard the clatter of the knife on the floor; he lurched towards the sound, at the same time reaching into his belt for his gun. It caught on the cloth; he rolled on the floor, but not quickly enough. The steel toe of a shoe crashed into the side of his head - his temple - and shock waves bolted through him. He rolled again, faster, faster, until he smashed into the wall; coiling upward on his knee, trying to focus through the weaving, obscure shadows in the near total darkness. The flesh of a hand was caught in the thin line of light from the window, he lunged at it, his own hands now claws, his arms battering rams. He gripped the hand, snapping it back, breaking the wrist A scream filled the room.

A scream and the hollow, lethal spit of a gunshot. An ice-like incision had been made in Bourne's upper left chest, the bullet lodged somewhere near his shoulder blade. In agony, he crouched and sprang again, pummelling the killer with a gun into the wall above a sharp-edged piece of furniture; Carlos lunged away as two more muted shots were fired wildly. Jason dived to his left, freeing his gun, levelling it at the sounds in the darkness. He fired, the explosion deafening, useless. He heard the door crash shut; the killer had raced out into the hallway.

Trying to fill his lungs with air, Bourne crawled towards the door. As he reached it, instinct commanded him to stay at the side and smash his fist into the wood at the bottom. What followed was the core of a terrifying nightmare. There was a short burst of automatic gunfire as the panelled wood splintered, fragments flying across the room. The instant it stopped, Jason raised his own weapon and fired diagonally through the door; the burst was repeated. Bourne spun away, pressing his back against the wall; the eruption stopped and he fired again. There were now two men inches from each other, wanting above all to kill each other. Cain is for Charlie and Delta is for Cain. Get Carlos. Trap Carlos. Kill Carlos!

And then they were not inches from each other. Jason heard racing footsteps, then the sounds of a railing being broken as a figure lurched down the staircase. Carlos was racing below; the pig-animal wanted support; he was hurt. Bourne wiped the blood from his face, from his throat, and moved in front of what was left of the door. He pulled it open and stepped out into the narrow corridor, his gun levelled in front of him. Painfully he made his way towards the top of the dark staircase. Suddenly he heard shouts below.

'What the hell you doing man! Pete! Pete!'

Two spits filled the air.

'Joey! Joey!'

A single spit was heard; bodies crashed to a floor somewhere below.

'Jesus! Jesus, Mother of...!'

Two spits again, followed by a guttural cry of death. A third man was killed.

What had that third man said? Two wise-ass stiffs and four crumb balls now. The moving van was a Carlos operation! The assassin had brought two soldiers with him - the first three crumb balls from the shape up. Three men with weapons, and he was one with a single gun. Cornered on the top floor of the brownstone. Still Carlos was inside. Inside. If he could get out, it would be Carlos who was cornered! If he could get out. Out!

There was a window at the front end of the hall, obscured by a black blind. Jason veered towards it, stumbling, holding his neck, creasing his shoulder to blunt the pain in his chest He ripped the blind from its spindle; the window was small, the glass here, too, thick, prismatic blocks of purple and blue light shooting through it, it was unbreakable, the frame riveted in place; there was no way he could smash a single pane. And then his eyes were drawn below to Seventy-first Street. The removal van was gone. Someone must have driven it away ... one of Carlos's soldiers! That left two. Two men, not three. And he was on the high ground; there were always advantages on the high ground.

Grimacing, bent partially over, Bourne made his way to the first door on the left; it was parallel to the top of the staircase; He opened it and stepped inside. From what he could see it was an ordinary bedroom, lamps, heavy furniture, pictures on the walls. He grabbed the nearest lamp, ripped the cord from the wall and carried it out to the railing. He raised it above his head and hurled it down, stepping back as metal and glass crashed below. There was another burst of gunfire, the bullets shredding the ceiling, cutting a path in the plaster. Jason screamed, letting the scream fade into a cry, the cry into a prolonged desperate wail, and then silence; he edged his way to the rear of the railing. He waited. Silence.

It happened. He could hear the slow, cautious footsteps; the killer bad been on the first-floor landing. The footsteps came closer, became louder; a faint shadow appeared on the dark wall. Now. Bourne sprang out of his recess and fired four shots in rapid succession at the figure on the staircase; a line of bullet holes and eruptions of blood appeared diagonally across the man's collar. The killer spun, roaring in anger and pain as his neck arched back and his body plummeted down the steps until it was still, sprawled face-up across the bottom three steps. In his hands was a deadly automatic field machine-gun with a rod and brace for a stock.

Now. Jason ran over to the top of the staircase and raced down, holding the railing, trying to keep whatever was left of his balance. He could not waste a moment, he might not find another. If he was going to reach the first floor it was now, in the immediate aftermath of the soldier's death. And as he leaped over the dead body, Bourne knew it was a soldier; it was not Carlos. The man was tall, and his skin was white, very white, his features Nordic, or northern European, in no way Latin.

Jason ran into the hallway of the first floor, seeking the shadows, hugging the wall. He stopped, listening. There was a sharp scrape in the distance, a brief scratch from below. He knew what he had to do now. The assassin was on the ground floor. And the sound had not been deliberate; it had not been loud enough or prolonged enough to signify a trap. Carlos was injured - a smashed kneecap or a broken wrist could disorient him to the point where he might collide with a piece of furniture or brush against a wall with a weapon in his hand, briefly losing his balance as Bourne was losing his. It was what he needed to know.

Jason dropped to a crouch and crept back to the staircase, to the dead body sprawled across the steps. He had to pause for a moment; he was losing strength, too much blood. He tried to squeeze the flesh at the top of his throat and press the wound in his chest, anything to stem the bleeding. It was futile; to stay alive he had to get out of the brownstone house, away from the place where Cain was born. Jason Bourne ... there was no humour in the word association. He found his breath again, reached out and pried the automatic weapon from the dead man's hands. He was ready.

He was dying and he was ready. Get Carlos. Trap Carlos... Kill Carlos! He could not get out; he knew that. Time was not on his side. The blood would drain out of him before it happened. The end was the beginning: Cain was for Carlos and Delta was for Cain. Only one agonizing question remained: who was Delta? It did not matter. It was behind him now; soon there would be the darkness, not violent but peaceful... freedom from that question.

And with his death Marie would be free, his love would be free. Decent men would see to it, led by a decent man in Paris whose son had been killed on the rue du Bac, whose life had been destroyed by an assassin's whore. Within the next few minutes, thought Jason, silently checking the clip in the automatic weapon, he would fulfil his promise to that man, carry out the agreement he had with men he did not know. By doing both, the proof was his. Jason Bourne had died once on this day; he would die again but would take Carlos with him. He was ready.