Disappearance in the Dangai

 is an event taking place in the Reigai Uprising. It focuses upon 7th Seat Kagerōza Inaba's rise to power, and the eventual overthrowing of the Shinigami from Seireitei.

Prologue
In Soul Society, the 10th Division captain Tōshirō Hitsugaya walks outside the 1st Division barracks, whereupon he is greeted by fellow captains Shunsui Kyōraku and Jūshirō Ukitake. Tōshirō is asked whether something happened to compel him to visit the Captain-Commander, but he states that he is merely filing a report on the Tenkaiketchu's cleansing. Kyōraku reassures him, stating that the process will be completed by the end of the day, which surprises Hitsugaya on the quickness of the task.

Kyōraku informs him that Nanao Ise, his lieutenant, told him of this, prompting Hitsugaya to berate his own lieutenant for her laziness. He apologizes, asking the two captains to report the details to the Captain-Commander. As Hitsugaya is leaving, Kyōraku comments that he sounded pretty upset. Ukitake reassures him, claiming that this is a good sign, and that getting angry over ordinary things shows that things are starting to return to normal. Kyōraku agrees, as they both stare out at the wide expanse of Seireitei.

Completed Cleansing! The Dangai Disaster
Meanwhile, in the Human World, Rangiku Matsumoto finishes the sealing of the Tenkaiketchu, and sighs with relief. She informs Nanao that she is done, who reveals that they have completed their share of the cleansing. Rangiku comments that she was surprised that they had to establish a barrier over such a wide perimeter, to which Nanao states that it was to be expected, as they had to swap part of Soul Society with Karakura Town. She comments that she never realized that they would be assigned to the Human World for a month to deal with the transportation phase.

Nanao notices Rangiku contemplating the one month since Gin Ichimaru's death, and asks whether she is alright. Rangiku brushes it off, asking whether the two of them should reward themselves for their hard work. Nanao laughs at this, prompting Rangiku to ask what is wrong. She comments that Rangiku is back to her good old self, revealing that she has been depressed the past month. They both start laughing, as Rangiku receives a call from her Denreishinki. She picks it up, promptly receiving an earful from her captain, who berates her for not filing the paperwork.

She apologizes, stating that she was working the entire time. Rangiku tells Hitsugaya that they have finished the assignment, and are now heading out to enjoy themselves, but he tells her to return to Soul Society immediately, despite her protests. Rangiku tells him that there is nothing wrong with having fun, but her captain states that they do not have time for "fun". Nanao tells her not to disobey her captain's orders, as Hitsugaya berates her over the phone. She opens a Senkaimon, as Rangiku grudgingly follows her inside. Two Jigokuchō accompany them on their journey, as they make their way through the Dangai.

As the Senkaimon closes, they are immersed in darkness, but are holding lamps to observe their surroundings. Rangiku comments upon the spookiness of this particular passageway, as Nanao agrees with this sentiment, stating that this is the only path from the Human World to Seireitei. Rangiku sighs, promptly turning to look behind her at the murkiness of the Dangai passageway. She calls to Nanao, asking whether she can sense something unusual. Her statement surprises Nanao, as the Jigokuchō behind her dissipates into energy. Rangiku's Jigokuchō follows suit, as she prepares to draw her blade at oncoming enemies. She wonders what is going on, as Nanao remains silent.

She wonders what is going on, as Nanao remains silent. Back in Karakura Town, Ichigo Kurosaki and Rukia Kuchiki return to the Kurosaki Clinic, whereupon Kon greets them. Kon charges at Rukia, who sends him bouncing around the room. Ichigo informs Kon that he wasn't to leave the room, but he states that no one is going to stop Rukia from giving him his daily hug. Kon explains how good Rukia's hugs feel, comparing it to a feeling of ecstasy, and states that he would never understand. Rukia heartlessly trods over Kon's plush body, as his Substitute Badge starts to blare out.

Ichigo comments that more and more Hollows have been manifesting each day, but Rukia tells him to let it go. He picks Kon up, stuffing his fist into his mouth, pulling out his Gikon. Ichigo scrubs the pill on his shirt, and leaves his body to Kon's devices. Kon is thrown into the nearby wall, as Ichigo tells Kon to behave himself. Before Kon can respond, Ichigo and Rukia leave the room, telling him to mind the place whilst they are gone. Chappy dances around happily in Rukia's body, as Kon attempts to ask her whether she has thought of questioning her will.

Kon sighs, as he senses a Senkaimon opening. As the gateway opens, an unidentified figure falls from it. As Ichigo and Rukia search for the Hollow, she reports that a Senkaimon opened nearby, but they dismiss this, focusing on the task at hand. As they run across the sky, Orihime Inoue, Yasutora Sado and Uryū Ishida call out to them, wondering whether they require assistance. Ichigo reassures them, stating that they will be able to handle it, as the group realizes that Ichigo hasn't needed to expend more reiatsu than usual, due to Rukia remaining in the Human World.

Kagerōza's Advice, The Unknown Girl Appears
At the 12th Division's Shinigami Research and Development Institute, Captains Kyōraku and Hitsugaya appear before Akon, reporting that their lieutenants have not reported in since yesterday evening. Hitsugaya asks whether he can see a record of Dangai traffic, to determine whether they have passed through successfully. Akon excuses himself, walking into the separate offices. He calls to Kagerōza Inaba, ordering him to bring a record of traffic throughout the Dangai. Akon comments upon the lieutenants' strange behavior, as Inaba comes forwards with a book in his hands.

He reveals to the captains that there is no record of them ever returning from the Human World, theorizing that they haven't left the Dangai yet. Hitsugaya is surprised at this statement, as Kyōraku states that this incident is getting stranger and stranger. Kon jumps down from a lamppost, scratching his head. He walks through the car park, wondering where he sensed the Senkaimon opening. He realizes that there is no-one there, stating that he should find a beautiful girl as compensation, rather than waste his precious free time.

Kon trips over a blanket on the ground, struggling to maintain his balance. He collapses onto the floor, wondering what happened. Kon notices a hand protruding out from under the blanket, and stumbles away in surprise, inadvertently removing the blanket. He realizes that it is a girl, and covers his eyes promptly. However, Kon is unable to keep his eyes off her, peeking through his fingers. He turns away, wondering what a naked girl is doing here. Kon puts his ego away, inquiring as to whether she is still alive. As he prepares to check her pulse, a passerby asks what Kon is doing, instantly proclaiming him as a pervert.

The Dangai Investigation
She calls out to the police, running away when Kon tries to silence her. Back in Soul Society, Captains Kyōraku, Ukitake and Mayuri attend a summons by the Captain-Commander, who states that he understands the situation. Yamamoto asks Captain Kurotsuchi of his opinion on this issue, who postulates that they must be still in the Human World, if their presence is not recorded in the Dangai archive. Hitsugaya states that he cannot believe Mayuri's statement, as it is out of character for them to disobey a direct order. Ukitake suggests that some sort of incident could have unfolded during Dangai transit.

Mayuri refutes this statement, claiming that the Shinigami Research and Development Institute monitors the Dangai every hour of the day, asking whether he is implying that the 12th Division missed something. Hitsugaya confirms this, causing Mayuri to become infuriated with him. The 12th Division captain approaches him, stating that Hitsugaya is blaming him directly for his lieutenant's negligence, but Kyōraku breaks up their argument, saying that he would prefer confirmation, rather than jumping to conclusions. A messenger interrupts the summons, appearing before the Shinigami captains.

He informs them that both lieutenants have returned from the Dangai, much to Hitsugaya's surprise. As they assemble before the Captain-Commander, Hitsugaya demands to know what kept them so long, as Rangiku is surprised by his harshness. Mayuri comments that the incident has made a mockery of his Institute, as Kyōraku inquires as to where they stopped off on their journey back. Nanao reveals that they came straight back after the cleansing, as Rangiku states that her captain berated her just a short while ago. The three captains are surprised by this revelation, as Nanao reveals that they finished three hours ago.

Ukitake realizes that the time axis is out of harmony with the other planes of existence, as Kyōraku states that there is indeed something wrong with the Dangai, much to Mayuri's contempt. Yamamoto states that he is adjourning the summons, announcing that he is calling an urgent captains' meeting. Yamamoto tells Captain Kurotsuchi to relay his findings to the other captains, who states that, after investigation of the Dangai data, he realized that there was a time disparity has formed between Soul Society and the Human World. He states that this disparity is rapidly expanding, and that intervening in the Human World will be impossible for the next couple of days.

Captain Retsu Unohana asks whether stopping the expansion is a possibility, to which Mayuri states that it was always a factor. However, he explains that he was more worried about the consequences of the solution, informing the other captains that he will undergo a survey of the Dangai before providing anything conclusive. Yamamoto decrees captain Mayuri Kurotsuchi in charge of the Dangai investigation, stating that captain Kenpachi Zaraki will join him as a means of security. The two captains are at odds with this assignment, as Mayuri asks whether he can provide a valid form of security, considering the possibility that he could throw everything into turmoil.

Yamamoto interrupts their argument, stating that 6th Division captain, Byakuya Kuchiki and lieutenant Renji Abarai are to assist Mayuri alongside Captain Hitsugaya. Back at the Kurosaki Clinic, Rukia and Ichigo are surprised by the sudden appearance of the unknown girl. He asks Kon who she is, who states that he isn't entirely sure, which is a problem. Ichigo berates him for bringing her here, considering that her presence is problematic. Kon states that it just happened, but Ichigo doesn't believe him, lifting up the blanket, ignoring Kon's warnings. His face explodes in the color red, as Rukia blushes. He covers the girl, asking Kon just what he has done. Kon denies that he has done anything wrong, commenting that he just found her lying unconscious like that.

Rukia turns her attention to the girl, stating that there is nothing emanating from the girl. Ichigo is confused, to which she explains that, normally, even if a Human had no reiryoku, a Shinigami would still be able to sense the being was human. But Rukia is unable to sense anything from the girl, as Ichigo asks where exactly Kon found her. He states that she was lying at the parking lot on the third street, as Rukia confirms that that was the location where the Senkaimon opened earlier. Ichigo wonders whether she is a gigai, but Rukia states that she cannot say for sure. She examines her Denreishinki, stating that she will send the report to Soul Society nevertheless.

Entering the Dangai! The Entrapment
Back in the Soul Society, Hiyosu receives Rukia's message, alerting Akon to its contents. Akon tells him that they have more pressing matters to deal with, but looks at the message anyways. However, Kagerōza Inaba enters the room, preventing him from looking at it. Akon tells him to direct Captain Kuchiki and the others through the Dangai, so they can conduct their investigation. He states that he shall, as Hiyosu announces that connections with Captain Kurotsuchi have been initiated. Inaba glances at the screen, as Mayuri berates his subordinates on their lateness. Akon apologizes, stating that they were experiencing difficulties adjusting it.

On the screen, a picture of the unknown girl is displayed, prompting Inaba to smile wickedly. Akon asks Mayuri whether he learn't anything about the incident, to which he confirms that the cause was not natural. Kenpachi Zaraki and his lieutenant walk through the Dangai floor, as lieutenant Yachiru Kusajishi's curiosity gets the better of her, poking and prodding the Dangai walls. As one of the globules on the wall explodes, she comments that this place is fun. Mayuri brings up the topic of Byakuya Kuchiki, asking whether or not they are ready. Akon reveals that they are about to enter now, as Kenpachi and Yachiru muck around behind him.

He berates them, stating that, despite the fixated nature of the area, the Kōryu will still respond to their presence. Mayuri comments that he does not mind whether they are turned into dust, but states that he will not allow for their interference in his study. Kenpachi observes this comment, asking what he will do to stop him. Mayuri comments that he cannot reason with fools, as reiatsu ripples thunderously throughout the Dangai. Nemu's survey equipment starts blaring out; informing Mayuri that something is rapidly approaching. As the three of them stare at the nearby wall, it starts to oscillate and froth, a bright yellow light emerges from it, encompassing them. At the Senkaimon in Soul Society, Byakuya Kuchiki and the other Shinigami emerge from the Dangai.

Numerous Shinigami, who are relieved to see them return safely, surround them. Byakuya asks what is wrong, to which one of them informs that communications was lost within the Dangai, and that Yamamoto has declared a state of emergency. Hitsugaya inquires of the two captains who entered the Dangai prior, but the Shinigami states that their whereabouts are unknown. He asks them where they are going, to which he states that they are going to the Captain-Commander. Byakuya reveals that they found an item of pivotal importance whilst in the Dangai. At Yamamoto's office, Ukitake is surprised that the Shinigami have not rendezvoused with Mayuri and Kenpachi. The Captain-Commander inquires as to what the item was, as Byakuya steps forth, revealing that the item was found near the preordained site in which they were meant to meet up with the others.

Byakuya comments that he is unsure as to its relevance in terms of this incident, as Ukitake is surprised as to the box's contents. He believes however, that the item will require thorough investigation, as Yamamoto is deep in thought. Back at the Urahara Shop, Rukia reveals to Kisuke Urahara and Tessai Tsukabishi that she revealed a summons from the S.R.D.I to appear alongside the Substitute Shinigami. She comments that she has never received an order like this, stating that she tried to receive confirmation of the event. However, Kisuke states that she would have lost connection with Soul Society, commenting upon the strangeness of this situation. He changes the subject to the unknown girl, asking how she is coping. Ichigo states that she is still sleeping, claiming that he wanted to ask who she is. He says that he will agree to go to Soul Society alongside Rukia, but Kisuke tells him that that isn't advisable.

He reveals that Yoruichi Shihōin returned to Soul Society several days ago, but states that she hasn't returned yet, despite informing him that she would immediately. Kisuke tells him that he should not travel there, in his current condition. Ichigo states that that is all the more reason why he should go, as Kisuke finds him agreeing with Ichigo's sentiment. He opens a Senkaimon outside the shop, informing Ichigo that, despite his reiatsu being stable as of this moment, it will gradually diminish. He continues, stating that, the more he puts strain on his powers, the quicker his reiatsu will dissipate. Kisuke tells Ichigo to keep that in mind when using his Shinigami powers, to which he states that he understands the limits his current state will bestow upon his body.

Rukia and Ichigo jump into the Senkaimon, kicking up a gust of wind. Kisuke wishes them both luck, telling them to be careful. As the two of them walk through the Dangai, Ichigo asks Rukia what is wrong. She states that there is something abnormal about it, asking Ichigo whether he hasn't noticed. Rukia reveals that there is not a single trace of reiatsu, explaining that, since a multitude of Shinigami traverse the Dangai on a daily basis, it should at least give off a wisp of reiatsu. However, Ichigo believes that this is so because the Kōtotsu cleans the Dangai. Rukia states that that isn't possible, considering that Sōsuke Aizen destroyed it one month ago. Ichigo recalls this event, as Rukia tells him to hurry along, so they can get out of there as soon as possible.

He turns to look behind him, noticing yellow pinpricks of light flashing in the distance. Ichigo calls out to Rukia, stating that it is coming. She asks him what is coming, as the Kōtotsu emerges from the emanating light, forcing them to flee from the imposing object. Ichigo wonders why it is here, as Rukia told him it was destroyed. Rukia states that she had never heard of its regenerating proceeding so quickly, as Ichigo asks how long it normally takes. She reveals that she doesn't actually know the time period, as Ichigo berates her for misleading him. As he runs across the pathway, his Substitute Badge slips out from his pocket, and is trapped in the Kōtotsu's path. Rukia tells him to forget about it, as the Kōtotsu increases rapidly towards them.

Ichigo releases his Bankai, black reiatsu immersing the two of them. He grabs Rukia, as they speed off away from the maw of the Kōtotsu. As they hurtle through the exit into Soul Society, Rukia asks whether he is alright, to which he states that he has things under control. However, he starts to collapse, as they both fall to the ground. Rukia asks what is wrong, as the two of them fall to the ground. As Ichigo emerges from the fall, he recalls Kisuke's warning imparted to him, standing up promptly clutching his head. As he staggers into the clearing, a figure calls out to him.

Aftermath
Captain Tōshirō Hitsugaya appears before him, as Ichigo is surprised to see him. He asks Hitsugaya whether he knows of Rukia's whereabouts, but he tells Ichigo not to move, drawing his blade against him. Hitsugaya tells Ichigo to throw down his sword and surrender, as Ichigo is surprised by his actions. The young captain charges at Ichigo, forcing him back. He locks blades with Ichigo, as Hitsugaya proclaims that Ichigo is under arrest as a material witness. He wonders what Hitsugaya is talking about, as the other Shinigami surround him. Byakuya points his blade at Ichigo, telling the Substitute Shinigami that he is just following orders. He states that Ichigo will be placed in confinement until further notice.

Meanwhile, in Kagerōza Inaba's secret laboratory, he places his glasses down on the desk, putting a pair of gloves on tentatively. Inaba picks up his cane, walking amidst the various troves of mannequins and bubbling tanks. He approaches Izuru Kira and Nanao Ise, apologising for taking so long. Inaba moves them out of the way, asking whether they should leave, a smile creeping across his face.