After the disappearances in Soul Society begin and the 9th Division Task Force that is led by Lieutenant Kuna and Captain Muguruma disappear in their investigation of the incident, Captain-Commander Yamamoto calls for an emergency meeting of the Gotei 13.
At the emergency meeting, Yamamoto reports that Kuna and Muguruma's Reiatsu have disappeared, and the reason is unknown. The Captain-Commander says that they must assume the worst until they know more on the situation. Until the previous day, the matter only concerned Rukongai, but Yamamoto declares it is now an issue which must be resolved on the pride of the Gotei 13. As Yamamoto says that he will send five captain-class Shinigami to the scene, Urahara makes a late arrival at the meeting. Urahara immediately requests to be allowed to go, but the Captain-Commander declines his request. Kisuke tries to argue with him, but is stopped by Yoruichi, who tells him not to lose his composure. She states that since he chose Hiyori to go on the mission, his actions are an insult to her. 
Because of this crisis, Yamamoto selects Captains Hirako, Rōjūrō Ōtoribashi, and Love Aikawa to go to Rukongai, while Yoruichi is to stand-by for separate orders. Captains Ginrei Kuchiki, Kyōraku, and Ukitake are told to guard Seireitei. Captain Unohana is told to prepare her medical facilities for incoming casualties. Unohana asks if it would not be better if she went to the scene to treat the wounded, but Yamamoto refuses to allow healers to go into an unknown situation.
As a result, he has decided to send others and invites the Kidō Corps Captain Tessai Tsukabishi and his lieutenant, Hachigen Ushōda to enter the room. Both Kyōraku and Ukitake are surprised to see the Kidō Corps’ top officers after a long time of not seeing them. Yamamoto notes that he assumes the two are aware of the current situation and asks them to head to the scene, to which both Shinigami accept the order.
As this occurs, Kyōraku notices Urahara’s worried look. He then remarks to Yamamoto that it is a bad idea to send both the captain and lieutenant of the Kidō Corps into an unknown situation. Yamamoto asks what he would suggest instead. In response, Kyōraku asks for his lieutenant to be sent. He then calls for Lisa, who had been eavesdropping on the meeting. As Kyōraku briefly scolds Lisa for eavesdropping, he checks with Lisa if she is willing to go the scene. Lisa agrees. Yamamoto notes how Kyōraku is doing as he pleases, to which Kyōraku replies that it is rare for such an event to occur, and he would like to give her some experience. He comments that Lisa is strong, and asks Tessai if he will step aside for her. Tessai concedes and Yamamoto finalizes the orders.
The meeting ends and the captains all begin to leave the hall as Urahara stands there stunned and worried. Kyōraku notices this, pausing at his side and placing a sympathetic hand upon Urahara's shoulder. He tells his fellow captain not to worry about the situation as Hiyori is a strong Shinigami but still not as strong as his Lieutenant, Lisa. He advises Urahara that waiting and having faith in their subordinates is also part of a captains duty. Kyōraku then leaves as a silent Urahara watches him go, his expression being one of worry and concern.
In Fugai Forest, outside the Seireitei, Hiyori is fleeing from an assailant, panting heavily as she does so. She is also injured with a number of wounds on her face. She is forced to evade attacks from a large shadowy, one of which causes a massive disturbance in the ground. Having dodged the attack, she stares at the massive figure, wiping blood from her face a swearing about her predicament. Her assailant moves in for another attack while Hiyori does not move to evade it.
As the attack is about to land, Shinji arrives on the scene and uses his Zanpakutō blade to block and parry the blow. Hiyori is stunned by his arrival, barely able to mutter his name. Shinji angrily chastises her and demands to know why she has not drawn her own blade. Hiyori insults him for this, her facial expression becoming downcast as she insists that she could not draw her blade against her assailant. The cloud moves away from the moon then and the added light reveals that her assailant is, in fact, Kensei and he's become a massive Hollowfied figure. Upon recognizing his fellow captain, this revelation greatly shocks Shinji.
While Shinji stands stunned, the others of the advanced team arrive on the scene. Love asks Hiyori if she is hurt before they too spy the tattoo on the Hollow's chest and realize that Kensei has become Hollowfied. Love demands to know what is going on while Rose wonders if the beast can really be Kensei consider the mask and other mutations that cover his body; he compares his appearance to a Hollow. Shinji agrees with them, not knowing whether or not the creature really is Kensei, but he implores his comrades asserting that if they do not draw their weapons, they will likely die.
Kensei lets out a loud Hollow cry along with a blast of Reiatsu, causing the group to split up to avoid him. Despite this, Kensei manages to get behind Love and catch him off guard. Before Love can do anything, Kensei punches him to the ground. The others yell out to him, concerned, but the captain remains standing with his blade drawn but is injured as a result, commenting that he wouldn't expect anything less from someone like Kensei. In the crook of Shinji's arm, Hiyori yells for them not to attack Kensei considering he is their fellow comrade.
Before she can finish what she is saying, Hiyori is overcome by a fit of coughing and convulsions. Concentrating on the situation at hand, Shinji advises her to remain quiet. As she regains control, Shinji insists that if the Hollow really is Kensei then that makes defeating him an even bigger priority than if he was a normal Hollow. Rose reinforces Shinji's opinion stating that Kensei is very strong, and thus they must stop him for that reason. Lisa draws her Zanpakutō while encouraging Hiyori not to worry about Kensei's safety given that there are many ways to stop him without having to kill him. Beside her, Rose also draws his blade.
Lisa informs Rose that she plans to cut Kensei's muscle tendons in order to disable his movement. She tells Rose to take his right side while she takes his left and the captain agrees. The two of them move in to attack the Hollow but their concentration on Kensei allows Mashiro, who has also been Hollowfied, to appear behind Rose and ambush him. Lisa notices her at the last moment and tries to warn the fair-haired captain but Mashiro manages to land a devastating kick on the top of his head, sending him crashing into the ground. The impact causes massive amounts of damage to the area and Rose lies injured among the debris as Lisa calls out to him.
Shinji is stunned to see that Mashiro has also gone through the same type of transformation that has affected Kensei. When he calls out her name, she notices him and immediately moves in to attack both he and Hiyori. Shinji is able to block her kick with his blade, causing an explosion around them as he struggles against her power. Hacchi suddenly arrives on the scene and surprises the Hollowfied Mashiro by using Bakudō #75 Gochūtekkan. He catches he off guard as the incredibly large pillars fall from the air and pin her to the ground.
Hacchi takes a moment to catch his breath and he complains, while panting heavily, that the entire advance team of Shinigami ran very quickly to the area and left him behind. While Shinji expresses his surprise at the arrival of their large comrade, Hacchi looks up and notices Love fighting against Kensei in the air. He raises his hand and closes his fist to use Bakudō #63 Sajō Sabaku, summoning thick yellow ropes that surround and then bind the upper body of the Hollowfied captain. Disabling him, the binds cause him to fall to the ground.
With the threat disabled, Hacchi calls out to Shinji and demands to know what is going on. He wants to know what Kensei and Mashiro have been transformed into Hollow-like beings. However, before he can finish his inquiries he is interrupted by an increase of Reiatsu coming from Kensei as he moans on the ground. Hacchi looks down and notices that the large ropes, that are binding the infected captain, are breaking apart. Hacchi is stunned to see the captain break free of the spell as he has never heard of anybody breaking out of a Level 60 binding spell using brute strength alone.
Outside the Twelfth Division barracks, a cloaked figure walks by in the dark. The individual is confronted by Tessai who comments that the cloak is an interesting new invention he hasn't seen yet as it completely blocks one's Reiatsu ans is, thus, quite extraordinary. Urahara reveals himself, smiling sheepishly, underneath the cloak, and Tessai asks him if he is planning on rescuing Hiyori. He advises Urahara that he thought this would happen when he saw Urahara at the meeting earlier and the inventor does not deny his intentions, realizing he should have known Tessai would guess his plan.
Tessai reminds Urahara that they spent a lot of time together at Yoruichi Shihōin's mansion whilst growing up, so he would not have failed to notice such things. Urahara wonders aloud whether or not Tessai is going to allow him to pass without incident but Tessai reveals that he does not intend on preventing him from helping his lieutenant. In actuality, Tessai seriously states that he cannot allow Urahara to go investigate the issue alone as he has been filled with an intense fear all evening. He beckons Urahara to hurry so they can get to the scene before any more horrors occur.
While this occurs, Kyōraku is walking around the Seireitei in the darkness keeping and eye out. He comes across two guards at the Fifth Division barracks and compliments them for keeping vigilant. Curious, they ask him if everything is alright but the Eighth Division Captain insists that nothing is wrong and that he is out because he couldn't sleep. Kyōraku spies Aizen carrying a pile of books back to his rooms and wonders if he was over-thinking matters. The guards question his meaning but he dismisses it as nothing, saying that Aizen seems to be having similar trouble sleeping. As the guards say good night to Aizen, Kyōraku tells them to get some rest and leaves.
After the guards bid him goodnight, Kyōraku returns to the Eighth Division barracks to find a small recruit standing in the yard alone holding a book. After some thought, Kyōraku asks if her name is Nanao Ise and the young Shinigami nervously confirms that she is honored he remember her name. Kyōraku asserts that it was easy given she's the youngest member of his squad and he always remembers the names of young ladies. Nanao asserts that she has come to read with her lieutenant but Kyōraku apologizes, revealing that Lisa is out on an important mission. He reassures her by maintaining he was sure she would return in the morning.
In Fugai Forest, as Kyōraku is speaking to Nanao about Lisa's mission and how she will return, his lieutenant is slammed into the ground by the Hollowfied Kensei. She is greatly injured by the attack with blood flowing from several wounds and also from her mouth. Her opponent moves in to attack her again but he is interrupted by an injured Rose who uses a blast of Kidō to get the Hollowfied captains attention. When Kensei turns towards him, Rose pleads with him to stop attacking as the Kensei he knew would never have attack a woman.
With a loud, angry cry, Kensei rushes toward Rose to attack but is caught by Hacchi when he uses Bakudō #99 Kin to restrain him. The spell summons the spiritual ribbons that binds Kensei's arms behind his back before wrapping the spiritual fabric around his entire body. It also pins Kensei with the spiritual fabric to the ground with several iron shafts in an "X" shape. The spell finally stops Kensei from attacking and puts an end to his rampage. The fact that Hacchi used Kin without incantation impresses Shinji, so he compliments his ability.
The high level technique takes a lot of effort from Hacchi who is panting and sweating heavily from the exertion of using the spell. He admits to the awed Shinji admits he might have overdone it with the Kidō. The group comes together and examines the Hollowfied Kensei. Shinji asks Hacchi if he can somehow heal him. Hacchi sadly denies that he can as he has no idea what exactly Kensei's condition is so it isn't within his power to help him. Still in Shinji's arms, Hiyori is overcome by another fit of coughs and convulsions and Shinji asks if she is alright. Still coughing wildly, Hiyori is unable to respond to him so Shinji asks Hacchi to start healing her due to her condition.
Hiyori manages to regain a little strength, weakly telling Shinji to let go of her. However before Shinji can react, a white substance begins to flow from Hiyori's mouth and, losing control, she draws her own blade and slashes Shinji across his left shoulder and collarbone. As Hollow mask forms on Hiyori's face and she lets out a Hollowfied cry as Shinji falls to the ground amid intense Reiatsu shasking around them. The others of the group stand stunned for a moment before Lisa calls out to her fellow Lieutenant. Love tuts and angrily demands to know what is going on.
Lisa and Love move towards Hiyori to try and help the situation. However, a sudden and complete darkness begins to envelope the area, catching everyone with the group inside, blinding them. Love hears cries of pain in the darkness but cannot see anything so he calls out to his fellow Shinigami. Before he receives any sort of answer, he is stabbed from behind and falls to the ground injured. The darkness that surrounds them all begins to dissipate and the perpetrator is revealed to be Kaname Tōsen who had used his Bankai to ambush them.
Lying on the ground wounded, Shinji tries to confront Tōsen about his crimes. He demands to know why he has betrayed them, especially Kensei, his own captain. Tōsen does not answer his question but someone approaches Shinji from behind and tells him that Tōsen did not betray anybody as he is a very loyal individual. Turning around, Shinji finds that the stranger is his own Lieutenant, Sōsuke Aizen who informs Shinji that Tōsen was following his orders and is loyal only to him. Aizen calmly requests that his subordinate is not blamed for this.
With the revelation that the true perpetrator is Aizen and not Tōsen, Shinji angrily reveals that he had suspected him all along and this is why he chose him as his Lieutenant, to keep an eye on him. Aizen reveals that he is grateful for Shinji's suspicions as it allowed him to fool him into not realizing that for this entire month, the man following him was not Aizen. He reveals the power of his Kyōka Suigetsu which allows him to make his enemies see what he wants them to see. He reveals the name of his ability, which he calls, "Complete Hypnosis".
As Shinji lies stunned and injured on the ground, Aizen reveals more about the situation that allowed him to carry out his plans. He asserts that had Shinji bother to get close to and interact with his lieutenant like other captains did then he might have been able to see through the deception. However, the reality is that Shinji kept Aizen at a distance and refused to learn about him. He maintains that Shinji has become his victim because he refused to learn anything about his subordinate and that allowed him to deceive him and carry out his actions behind his back.
Aizen elaborates on the situation revealing that a Lieutenant can also reject the offer to be promoted by a Captain. However, Aizen insists that he did not reject Shinji's decision because the situation was ideal, that he knew Shinji was suspicious of him from the beginning. Thus, instead of Shinji choosing him, in reality, Aizen chose Shinji. He goes further to wonder if Shinji should apologize to those also injured around him as it was his actions and his refusal to learn about Aizen that caused their injuries. The taunts enrage Shinji to the point he is able to get to his feet to attack.
When Shinji moves to attack his treacherous subordinate, he is stopped when a familiar white substance explodes from the side of his face and the sound given to him by Hiyori. While Shinji panics about being infected as well, Aizen calmly thanks him for rising to his slight provocation. All around him the white white substance begins forming on the faces of those lying wounded nearby. Shinji angrily demands to know what is going on and what Aizen wants. His Lieutenant merely comments that he had originally believed agitation sped up the Hollowfication but now he has confirmation.
Stunned, Shinji demands to know what Hollowfication is but Aizen calmly asserts that he does not need to know what it is. Shinji is overcome by his condition, screaming in pain. A masked Hiyori, who is still on her feet, notices her comrades cry and hesitantly calls out to him. When Aizen realizes that she is still standing, he motions to Tōsen to cut her down. Despite Shinji's desperate pleas, Tōsen carries out his order with hesitation, cutting down Hiyori with a single slash of his blade. Aizen advises Shinji that it is time to end everything, thanking Shinji for being the perfect captain. He advises him that the betrayal he does see is trivial compared to the betrayal he doesn't see.
With his blade drawn, Aizen prepares to kill Hirako and calls them all wonderful test subjects. Hirako curses, causing his Hollowfication to advance. However, Aizen is then stopped by Urahara in his Reiatsu blocking cloak. Urahara cuts off Aizen's division insignia armband. As Aizen, Kaname and Gin notice the arrival of Urahara and Tessai, Aizen remarks that they have yet another interesting guest.  Urahara and Tessai then confront Aizen, Kaname, and Gin on what they were doing. They also attempt to save the Hollowfied Shinigami.
|Major Participants||Gotei 13 • Shūhei Hisagi • Suì-Fēng • Byakuya Kuchiki • Sōsuke Aizen • Gin Ichimaru • Kaname Tōsen • Tessai Tsukabishi|
|Battles & Events||The New Captain of the 12th Division • Recruit from the Nest of Maggots • Disappearances in Soul Society • Battle in Fugai Forest • The Fall of Kisuke Urahara|