In an empty street, in the far west of the sereitei, their flight ended

The figure that stepped into their path, sword drawn, wore a sleeveless haori: a black man with long hair braided into a mantle of dreadlocks, his bare arms tightly muscled. He had come from nowhere, but, suddenly, his presence was everywhere. Renji, who had been tugging Rukia along by the hand, pulled her close and reached for his sword.

"Abarai Renji."

"Tousen-taichou."

"You are aiding and abetting criminals. You are to come with me. Now."

"No."

"I don't believe I gave you a choice." He swung his sword down and planted the tip in the dusty ground, and the air around him began to roar.

Rukia threw up her hands to cover her ears as the sound increased, shaking loose dust and mortar from the buildings around them. Renji's hold on her was so tight that it hurt her, while, all around, ribbons of energy began to rise up from the earth. They were like spirit ribbons, the threads of souls, but, so far as she could tell, they belonged to no living thing. They encircled the three shinigami, warping the air as they spiralled upwards. Not just the air. They were changing the very space around them. Within moments, Rukia could no longer feel the ground beneath her feet. It had lost all substance and the only constant in that storm was Renji's arm around her body, pinning her to his side. Then there was a sense of falling. Her feet scraped across stone, and she realised that she was moving with some speed. All at once, the ribbons fell away and she and Renji sprawled forward onto a plateau, red with the light of sunset. She could feel grit and broken rock against her knees, but it was Renji's exclamation that made her raise her head and look around:

"The sokyoku!"

And there before her was the vast plateau and the broken instrument of her execution. The nightmare was starting again, except that now the scene had changed. A strong wind was blowing in from the mountains, hauling along silvery white clouds that were piling like snowdrifts in the horizon. The crowd of soul-reapers who had come to witness her death were gone and, in their place, stood three figures, their robes stained gold in the fading light.

Three captains.

There was Tousen of Ninth Division, who had used kido to bring them here, Gin of Third Division, who stood at the base of the sokyoku, turned away from them as if to guard an imagined perimeter and, approaching them now, Captain Aizen of Fifth Division. The man who had been reported dead.

Renji pulled Rukia to her feet as Aizen approached. He was just as she remembered him: quiet, amiable. A soft smile on his lips. A gentleness to his movements.

"Please hand over Kuchiki Rukia," he said, his voice sweetly reasonable.

Renji's hold on her tightened. She had started to tremble. The sheer power that was rolling off of the man in front of her was making her body heavy; the pressure was building in her head. She wondered if this really was Aizen or if the reports had been true and this was an imposter, like the hollow that had taken over Kaien's body. If her instincts were right, then he was still holding back some of his reiatsu. "Abarai Renji," Aizen addressed the vice-captain who held her: "You have no part in this. If you relinquish her now, I will let you go."

"You're not having her!"

"Renji," she whispered, both moved and horrified by his defiance. Aizen's spiritual pressure was like a sheer force of nature and Renji's words like a declaration of war on a whirlwind. But he knew that too because, as Aizen advanced, he took a step back, retreating, his sword angled across both their bodies. Another step back. Buying them time.

"I'll ask you one more time. Will you hand over Kuchiki Rukia?"

"No."

"Alright then."

Rukia didn't see him move. Indeed, Aizen's progress across the plateau, until then, had been marked by a casual lack of urgency, but now his figure blurred. The next thing she knew, Renji's body rocked backwards and there was the wet sound of a blade punching through flesh.

Aizen froze with his sword still embedded in the younger man's shoulder. Renji's eyes rolled up in pain. With an expression of placid curiosity the Captain of Fifth Division withdrew his blade in a single, precise motion that jerked Renji forward. Blood splashed into Rukia's face as her friend crumpled, pulling her down with him. His hold on her never let up. He was on his knees now, his arm still wrapped around her waist. She twisted in his grip and pressed her palm against the wound in his shoulder, but the blood was pumping too fast.

"Renji, please," she whispered. His eyes were focussed again, trained on Aizen. She might have said more had a sound like a crack of thunder not ripped through the sky. Suddenly, a woman's voice was speaking all around them:

"This is Vice-Captain Kotetsu of Fourth Division. This is an emergency transmission to all members of the Gotei Thirteen and to the ryoka. All of what I am about to tell you is true." Rukia could feel the kido crackling in the air about them; the thin lines of a communication net, carrying the woman's words: "The Central Forty-six are dead. I repeat: the Central Forty-six are dead. They were murdered before the crimes of Kuchiki Rukia were brought to trial and those orders are henceforth repealed. Sosuke Aizen, Kaname Tousen and Ichimaru Gin are now wanted for the murder of the governing council. They will be held to account for their actions."

"You bastard," growled Renji as the broadcast ended. Aizen had taken a step closer. "What did you want with her?"

"What did I want? What do I want? Are you going to let her go or not?"

"Of course not! Shut up, Rukia," he added as she started to object.

"Alright then, go ahead and keep a hold of her, but you'll lose that arm of yours." His figure blurred. Rukia flinched, but the blow that should have fallen never came and, instead, metal clashed with metal.

"Ichigo!"

For a brief and nightmarish instant, she thought the human boy had taken the brunt of the attack because she could no longer see his thick butcher's-knife blade. Then she realised that the zanpakuto he carried had changed. A long, tapering black sword now held back the force of Aizen's strike. His shihakusho had altered too: it was still recognisably a shinigami uniform, but instead of the kimono over his juban, he was dressed in a full-length black coat that split and flared out at the top of his waist. The lining was blood red.

The energy that spilled off of him was different even to that which she had felt on the sokyoku. It was darker. Stronger. She recalled Urahara's words to her back in the human world; he had told her that this boy was dangerous. She had thought then that he meant Ichigo's power was too great to be wielded by a human, that he ran the risk of its burning out of control. Now she wondered if he'd meant the opposite: that the danger would manifest the very moment he gained control of that strength, the moment he realised what he was and what he could do.

He had gritted his teeth against the weight of Aizen's blade pushing down on him:

"Renji, I told you to get her out of here!"

"There were some unforseen challenges," said the shinigami, lurching to his feet. Rukia wrapped her arms around his waist, partially to bear his weight and partially to let him take hers. Her head was swimming with the pressure.

"As for you," Ichigo said, his voice a warning as he turned towards Aizen: "You did this to Rukia. You sent Byakuya and Renji to the human world. You locked her in that tower. It was all you."

"Ichimaru Gin!" called Aizen. If anything, he sounded amused: "I thought you were in charge of stopping anyone getting in my way."

"Sorry, Aizen-taichou. You said that I should stop any shinigami climbing to the sokyoku. But this one's a human." The Third Division Captain smiled at his own joke.

"Well, no matter." Aizen's figure blurred and Ichigo staggered forward as the weight that had been bearing down on his sword suddenly vanished. The Fifth Division captain reappeared some distance away, between Gin and Tousen: "You've grown stronger, Ichigo Kurosaki, but you must be able to sense the massive power difference between us. You cannot fight me."

"There must be something we can do," said Renji in a low voice.

"Yeah, we're going to fight him. Together. In bankai."

"What?" whispered Rukia, but Ichigo had turned back to his opponent:

"On my word," he said. Rukia saw him steel himself with a deep breath. "Now!"

Renji raised his sword and, with his other hand, pushed Rukia backwards, away from his body. She caught just the edge of his spiritual pressure as it was released: an energy a hundred or a thousand times greater than that of the man she knew and yet it was his. Of that, she had no doubt. Dust spiralled up from the ground at his feet as the sword he held transformed. Bankai, the full release. The blade itself disappeared. In its place, the air and the sky all around was filled with a writhing mass of bones.

In bankai, a weapon was capable of manifesting itself in an entirely new form, that of the most potent aspect of the bearer's soul. For Renji, it appeared as a skeletal beast with the body of a snake and the fanged skull of a baboon. It had no flesh nor hair save for a ruff of red fur about its neck. The boney segments of its body connected by glowing threads of reiatsu.

As if echoes of this manifestation had hooked themselves onto Renji's figure, he now stood, bare-chested, with a fur stole across his shoulders and a string of white baboon's teeth around his neck. Bankai turned the soul inside out, the deepest parts of it taking solid form. Even now, she could see it in Renji. For all his rank, he had never fully outgrown the streets of Rukongai; something of the beast and the scavenger would always remain. For her, it was the imprint of ice, the cold singularity in her own heart. Their souls had been forged in a harsh world. If ever they were tempted to forget, they need only look at the forms their power took.

"Howl, Zabimaru!" Renji roared the sword's incantation in the same moment that Ichigo's figure blurred and reformed blade to blade with Aizen's. The baboon-serpent lunged forward. Rukia couldn't see what happened next because the forms of the three men in combat faded in and out of existence, moving too fast for her to follow. This was Ichigo's bankai, she realised: the change in his sword and clothes. He was much faster now. Instead of the violent fluctuations she usually felt in his reiatsu, a pitch dark energy now flowed smoothly through his body. Where it leaked out, the ground around him broke apart and shafts of dust skittered into the air, borne up by spiritual pressure.

Yet, despite their extraordinary strength, neither Ichigo nor Renji seemed capable of touching Aizen. Rukia saw Ichigo flung backwards, his reiatsu kicking up a sheer of dust where he struck the ground. Aizen dodged Renji's bankai, raised his sword and cut straight into the beast's skull.

The wave of pressure that rolled out from that blow reached Rukia on the edge of the plateau. As it broke against her body, she dropped to her knees and put her arms up. A tide of dust followed. It grazed her skin. When she was able to look again, the bones that had formed the serpent's body were scattered across the plain, disarticulate. To her left, Ichigo gasped. His gaze went to Renji, who was doubled up in pain, and his face hardened:

"One shot!" he called to Renji: "We're going to get one shot at this."

"This may hurt, but one more time, Zabimaru," Renji muttered under his breath and, all around him on the battlefield, the serpent's bones lit with spiritual energy. As Rukia watched, they rose into the air and drifted towards each other. One locked to another, forming the animal's long spinal cord. When Renji lifted the hilt of the sword, the whole length of its body flexed into the air like the crack of a whip. "Howl!" he cried and Rukia felt the energy that rushed through him like a storm surge. In the same instant, Ichigo's figure blurred. Aizen's too.

A stark black line appeared down the length of Zabimaru as a sword swept through its body. This time, the bones crumbled as they burst apart. A rain of white stones falling on the plateau.

Aizen reappeared just inches from Renji, his sword thrust forward into the younger man's chest. His movements had been too fast to see, but his last action was to wrench the sword out of Renji's torso and sweep the blade across his throat. The light went out of his eyes. Rukia screamed as blood flowed down his front. Ichigo appeared, just metres away, his face pale. He roared with anger as he turned his sword on Aizen.

His blow should have cut through the captain, head to toe, but it was stopped short, not by the older man's blade, but, instead, by the crook of his finger.

The gentleness of Aizen's facade gave way to an expression of cruel delight:

"Do you see now, the difference between you and I?" he asked and, as he spoke, he sunk his own sword deep into Ichigo's belly. The human's boy's head jerked back; his back arched in a convulsion.

Aizen merely shook him from the sword like a fisherman shaking his catch from a spear.

A silence followed. Rukia still knelt on the edge of the plateau, her mind empty. The three captains approached, their reiatsu, a vast weight.

Aizen reached her first. He leant down, hooked his fingers into the collar she wore and lifted her. At his touch, her body fell limp. He wrinkled his nose. "It would be easier for me if you would walk by yourself," he said. Then realisation dawned in his eyes and he smiled: "Ah, I'm sorry. I forgot. The past few months in seki-seki will have drained your reiatsu to such an extent that you are probably unable to stand this energy. Am I right?" When she didn't answer, he added: "No matter." He held her at arm's length from his body. Any closer and she might have lost consciousness. The tips of her toes touched the plateau beneath. She had just enough strength to lift her head and keep from choking. "You're probably wondering why I brought you here and went to all this trouble," Aizen said as he half-carried and half-dragged her back to the suffocating presences of the other two captains: "My goal was never the sokyoku as many believed. Its power is nothing compared to the power I crave. Rather, you were my target, Kuchiki Rukia, or, at least, the power inside you."

His words reached her, even through the fog of reiatsu: "There is a limit," he was saying: "To the power it is possible for a shinigami to attain. And a limit for a hollow too. There is only one way to surpass these and that is for a soul-reaper to take the power of a hollow. Urahara Kisuke knew this and he was working on a device that would achieve just that, a hundred years ago, Once it was completed though, he knew that there was no way for him to control the power within it. It was dangerous. But he knew of no way to destroy it and so he decided to hide it and the hiding place he chose was you, Kuchiki Rukia. Your soul."

Waking up in a dark alley, a man standing over her, a parasol in one hand, a fan in the other. Kisuke in his ridiculous striped hat, his head cocked on one side as he surveyed her injuries:

"Looks like you could use some help," he had said. The hollow's bite had broken her ribs and scraps of bone had torn into her lungs. She should have died that night, eight days into her mission in the human world, but he had saved her.

"Your gigai was no ordinary gigai, " Aizen said, taking pleasure in the faint understanding that lit in her eyes: "Did you not notice that, instead of returning, your spiritual pressue was fading, becoming less each day. The gigai you were wearing was designed for that, to completely drain the reiatsu of its host."

"Bastard," came a familiar voice. Rukia couldn't turn her head, but she recognised it as Ichigo's. His outburst had been weak and she waited to see if he would speak again. The wound had been to his stomach. It might take time to kill him. Aizen smiled over her shoulder at the human boy:

"You can still move. That's very impressive. Since you haven't the strength to stand, you will simply have to watch."

"Aizen!" That was someone else. Rukia couldn't see the man who spoke, but she could sense his reiatsu. It was unfamiliar to her. Almost as strong as Aizen's, and she felt the man who held her tense:

"Gin!" snarled Aizen. The white-haired captain, who had tormented her outside the Shrine of Penitence, stepped forward and she was passed into his hands like a parcel exchanged between business partners. Gin held the collar with a casual disregard for the woman wearing it. He tugged her to his side where, as he lowered his hand, she sunk to her knees. The backs of his knuckles pressed against her throat.

Too late, she realised that she couldn't breathe.