Invasion of the Shinigami World

 is an event taking place during the Bount Invasion that marks the beginning of Jin Kariya's plan to destroy the Seireitei as revenge for the purge of the Bount.

Prelude
In the air above Soul Society, a portal opens as the Bount fly out in streams of energy and fly across the sky. Meanwhile, in the meeting room in the First Division barracks, Captain-Commander Genryūsai Shigekuni Yamamoto commences the regular captains meeting with the other captains standing before him. Revealing that they have confirmed the presence and intrusion of Ryoka, Yamamoto instructs the divisions to assume their second-class alert positions.

Following this, Yamamoto tasks 10th Division Captain Tōshirō Hitsugaya with apprehending the Bount in light of the seriousness of the situation, which Hitsugaya acknowledges, and asserts that he must be extremely careful in gathering and sending information to the other divisions since the Shinigami Research and Development Institute has had a problem with information leaking recently before ordering the captains to kill any Ryoka they encounter without hesitating, leaving Hitsugaya to narrow his eyes.

Invasion
Elsewhere, the denizens of the Rukongai see the Bount flying above them and wonder what they are, only to flee in terror upon seeing that one of the energy streams is approaching them as the energy crashes into the ground, sending several villagers flying and creating a giant sphere of energy that dissipates to reveal Jin Kariya and Gō Koga in the clearing dust. Back in the First Division barracks, Hitsugaya walks through the hallways with his 7th Seat, Kōkichirō Takezoe and two other subordinates, where he inquires about whether any of the other divisions have moved out to begin searching for the Ryoka yet.

After Kōkichirō informs Hitsugaya that 2nd Division Lieutenant Marechiyo Ōmaeda left with some Shinigami from his division, one of the other Shinigami reveals that 7th Division Lieutenant Tetsuzaemon Iba has also departed for the Rukongai. In response, Hitsugaya instructs his subordinates to keep gathering information and reports from all the divisions before ordering them to not let any information leak, which they firmly comply with. Meanwhile, in the Rukongai intersection, Koga looks around at the buildings and comments on how quiet the surrounding area seems to be, only for Kariya to smugly assert that it will be loud soon enough.

Suddenly, Kariya and Koga are confronted by Marechiyo, who eats a rice cracker from a bag and stands before his subordinates while declaring that he will be first to fight the Bount, only for Iba to step in behind Kariya and Koga with his Shikai and contest this as he criticizes the nerve of the Bount to attack the Shinigami in broad daylight. When Koga requests that he leave this to him, Kariya obliges since it would provide a good test for them and steps to the side, leaving Koga to summon his Doll, Dalk. After intimidating the Shinigami with her assembly, Dalk relishes in how delicious the air is and how good it makes her feel.

With Iba describing this as a strange technique typical of the Bount, Marechiyo accuses Koga of being a coward who cannot fight with his own power, but a smirking Koga simply snaps his fingers, causing the Reishi comprising a nearby roof and bell tower to begin breaking off from the structures and flowing into his body, causing him to glow with a blue aura. While Marechiyo and his subordinates stare in astonishment at this and Iba demands to know what he is, Koga rebuffs their assumption that he is some kind of monster and claims to merely be a better-than-average Human, leading an angered Marechiyo to have his men rush forward and attack Koga.

At Koga's command to crush them, Dalk glows with the same blue aura and proclaims that she is feeling great as well before detaching and throwing her upper left arm, which reverts to its previous state of dozens of small metal spheres that the Shinigami are forced to defend themselves from with their Zanpakutō. While firing more spheres at Iba, who struggles to defend himself with his Shikai, with her lower body, Dalk opens fire on the Shinigami with the stump of her upper left arm, resulting in the Shinigami falling over incapacitated after several of the spheres slam into their bodies as Marechiyo watches in disbelief and astonishment.

Behind Koga, a panting Iba remains standing and berates him for underestimating the Shinigami while Marechiyo frantically looks around for someone else to fight for him. Reveling in her newfound strength, Dalk separates her body into dozens of medium-sized spheres that she begins swirling around Marechiyo, who rapidly slashes at them with his Zanpakutō in an effort to protect himself. After criticizing this as needlessly wasting energy as she watches with her floating head, Dalk begins slamming the spheres repeatedly into Marechiyo's body from all sides before one hits him in the head, knocking him out and causing him to collapse.

A concerned Iba puts aside his distaste for attacking unarmed opponents and moves into the air with Shunpo before coming down on Koga with his Shikai, only for the latter to effortlessly grab the blade by its single prong mid-swing, leaving Iba suspended in midair while he wonders what is going on. Upon seeing this, Dalk fires a sphere on a tether from her lower end that wraps itself several times around Iba's neck and proceeds to fire more spheres from another opening on her lower end, resulting in Iba being hit several times and falling to the ground as he lets go of his Shikai, where Dalk yanks him away by the neck, causing him to roll over to Kariya.

Unimpressed by Iba's poor showing despite his status as a Shinigami, Kariya levitates him into the air and blasts Iba away with a gust of wind, sending him crashing through a wall and into a building, the former of which collapses complete and the latter of which visibly sinks into the ground from the impact. After Koga returns Dalk to her sealed state, Kariya inquires about how he feels, prompting Koga to express satisfaction at how good he feels and at the unlimited amount of highest-quality Reishi in the area. Pleased by this, Kariya decides that they should depart and walks away with Koga, leaving dust billowing from the wreckage of the house behind him.

Some time later, Hitsugaya and his subordinates run up to the site of the conflict, where they are aghast to find Marechiyo and the other Shinigami lying defeated on the ground. Instructing Kōkichirō to contact the Fourth Division, which he runs off to carry out, Hitsugaya orders his other subordinates to assume defensive positions and assess the extent of the damage. While one of the Shinigami runs to Marechiyo's side and attempts to rouse him, Hitsugaya looks inside the house and is informed that Iba is the one lying within, though he is relieved to learn that the latter is conscious. Suddenly, Hitsugaya is contacted by his lieutenant, Rangiku Matsumoto.

Rangiku appears in front of Hitsugaya with Shunpo and states that she only just returned before apologizing for failing in her mission to prevent the Bount from reaching Soul Society, though Hitsugaya counters that he is the one responsible for this as the one who assigned her to the Human World and assures Rangiku that she does not need to worry about it. When asked by Hitsugaya about what she has learned, Rangiku explains that it is difficult to track the Bount and that she can only detect the Reiatsu of the two lieutenants even at the scene of the battle, an irritated Hitsugaya tells his men that they will continue the investigation and welcomes Rangiku back.

Elsewhere, Ichigo Kurosaki and Rukia Kuchiki stand on a grassy plain overlooking a distant mountain range and observe that they are back in Soul Society again. Upon being asked by Ichigo if she sensed the Reiatsu earlier, Rukia confirms this and describes it as seeming like a Shinigami was fighting the Bount, only to affirm in turn that she could not detect the Reiatsu of the Bount just like in the Human World, leaving her and Ichigo to ponder this in silence. Sliding in front of them, an annoyed Yoruichi Shihōin questions why they are pondering such things in an emergency situation while Ririn admonishes them for standing together like lovers.

With Ichigo staring in confusion at this and Rukia demanding to know what she is talking about, Ririn asserts that it feels bad for a reason that she cannot pin down, and when Kurōdo reminds her that they will lose to the Bount if they fight with each other while standing behind her with an agreeing Noba, Ririn claims to not care. As they run up to Ichigo and the others, Orihime Inoue, Yasutora Sado, and Uryū Ishida reveal that Kūkaku Shiba has moved her house again, which leads Yoruichi to note that she still likes to do so frequently and admit that she has a feeling about where Kūkaku moved to when Ichigo asks her about it.

As the sun begins to set in Soul Society, Ichigo and his friends walk along a dirt road, and as night falls with a full moon illuminating the area, Ichigo expresses surprise at having found Kūkaku's house, which is now located in the middle of a lake with wooden piers leading to it. After Uryū is left unnerved by Sado's nostalgic reaction to seeing the house, Yoruichi is left exasperated by Kūkaku's usual lack of aesthetic vision in addition to her standard redesign of the house, causing an unimpressed Ichigo to compare its quality to Rukia's drawings. When Rukia punches him in the face and tells him to be silent, Ichigo states that this role is supposed to belong to Kon.

However, Ichigo realizes that Kon is not currently with the group, and as Ririn asserts that she is certain Kon came with them to Soul Society, a concerned Orihime wonders if they should split up and look for Kon, though Kurōdo assures her that Kon will be fine since he is bursting with energy, which the group nods in agreement with. Suddenly, Ganju Shiba screams in pain within Kūkaku's house, startling the group. Meanwhile, in the Rukongai, Kon walks down one of the streets and criticizes himself for being the only one to get lost after coming all this way. Up ahead, several villagers gather around the damaged wall and house as one of them warns the others to not enter.

Curious about what is going on, Kon politely asks the villagers about what happened here, only for them to be shocked by his appearance and assume that he is some sort of monster who destroyed the wall and house behind them. Despite Kon insisting that he is a Modified Soul and could not do what they are accusing him of, the villagers begin chasing after him with the intention of killing him before he can do any more damage, resulting in Kon fleeing from them while abjectly refusing to die here. Back at Kūkaku's house, Ichigo and his friends watch with embarrassment and pity while Kūkaku angrily pins Ganju to the floor by his head with her foot.

When Kūkaku reminds him that he was dispatched to the Human World to help with the strange situation that Yoruichi mentioned to her, Ganju confirms that this is true, which prompts Kūkaku to lift him up by the collar and berate Ganju for forgetting about this because he was preoccupied with working at a convenience store before throwing him against the far wall, where he slides down after impact. With Yoruichi observing that she is the same as ever and Kūkaku apologizing for not being more helpful, Ichigo inquires if Kūkaku knows what convenience stores are, only for Kūkaku to emphatically declare that she does and question if this is a problem.

Presuming that Ichigo is making fun of her, Ichigo grabs a nervous Ichigo by the collar and points out how she is in a bad mood right now as she throws him against the far wall as well, where Ichigo slides down next to Ganju and is warned by him to not say anything unnecessary. Despite Ichigo's confusion about what he said wrong, Kūkaku promises to sort both of them out, causing Ichigo and Ganju to scream in terror and flee from her around the room while Rukia observes that one's mouth can get them into trouble around Kūkaku. Some time later, with a battered Ichigo and Ganju sitting tearfully before Kūkaku alongside their friends, Yoruichi finishes recapping the situation to Kūkaku.

After bringing up how Kariya said that the Bount were going to Soul Society for revenge since they were created by the Shinigami Research and Development Institute, Yoruichi notes that there is almost no record of them in Soul Society and attributes this to a cover-up of an unsavory incident. Though she does not know how the Bount will enact their revenge, Yoruichi reminds Kūkaku that it is not easy to get into the Seireitei since it is surrounded by a wall, which leads Kūkaku to deduce that Yoruichi wants to look into what the Bount are thinking and doing. As she confirms this, Yoruichi requests that Kūkaku let them stay at the house despite their numbers.

With Yoruichi pointing out how it will be easier to search the vast expanse of the Rukongai if they can stay here, Kūkaku confirms with Koganehiko and Shiroganehiko that they can feed so many mouths at once and blames Ganju's mismanagement of the situation for the Bount being able to invade Soul Society. Stomping Ganju's head to the ground again when he protests this, Kūkaku permits Ichigo's group to stay in her house despite its cramped nature, and when she wonders how they are going to track down the Bount, the Mod-Souls leap forward and present themselves, only to fall over in shock when a surprised Kūkaku questions what exactly they are.

Ichigo explains that the Mod-Souls were developed by Kisuke Urahara, causing a delighted Kūkaku to pick up and examine Noba while admitting that she never would have thought to put a Modified Soul inside a plushie, though Ririn and Kurōdo deny that this is worth being excited about when she attributes this decision to Urahara. Getting everyone's attention once more, Yoruichi asks Ichigo and his friends to collect information on someone named Ran'Tao, to their confusion, and elaborates that the lead researcher of the Soul Society project that created the Bount mentioned by Kariya during his recount of the history of the Bount was Ran'Tao.

As Rukia expresses disbelief at Ran'Tao still being alive, Yoruichi clarifies that it has been over 1000 years since Ran'Tao was expelled from the Seireitei and that Ran'Tao is rumored to live in the depths of the Rukongai now, leading Ichigo to conclude that they may be able to learn something about the Bount if they track down Ran'Tao, which Yoruichi affirms. Deciding that it is time for them to have dinner, Kūkaku instructs Koganehiko and Shiroganehiko to make preparations, which prompts them to march away, and Orihime observes that it has been a while since she had anything to eat while Uryū thanks Kūkaku for her hospitality.

With Ichigo and his friends departing for dinner, Kūkaku calls out to Yoruichi, causing her to stop and turn around, and inquires if Yoruichi has anything else to tell her. Though Yoruichi acts like she does not know what this means, Kūkaku instructs her to not play dumb and questions why Yoruichi is not going to the Seireitei before observing that it is not simply due to the convenience of her house. After hesitating for a few seconds, Yoruichi reveals that Maki Ichinose is helping the Bount and can turn invisible in addition to being able to completely conceal his Reiatsu, which has already allowed him to break into the Seireitei, to Kūkaku's surprise.

Yoruichi elaborates that Ichinose is also the one who sealed the database in the archives of the Shinigami Research and Development Institute and manipulated the data so 12th Division Captain Mayuri Kurotsuchi would become interested in the Bount, which she describes as falling for a simple trick, and provide Uryū with the Quincy Bangle so the Bount could enter Soul Society. While Kūkaku infers that Yoruichi is hiding somewhere that Ichinose cannot track her movements from, Yoruichi states that it would be hard to stop Ichinose from breaking in again even with 2nd Division Captain Suì-Fēng secretly strengthening security, which Kūkaku agrees with.

When Yoruichi brings up how it would also be too much of a pain for her to return to the Seireitei as someone who fled from Soul Society before, a grinning Kūkaku asserts that this sounds like the real reason, and as Yoruichi says that she will be doing things her way, Kūkaku asks her if they can win, prompting Yoruichi to admit that she does not know. Despite this, Kūkaku promises to help Yoruichi out regardless because she loves trouble. The next morning, Ichigo and his friends stand on the bank of the lake, where Rukia declares that they will split up from here and instructs her friends to use the Mod-Souls to search for the Bount across Soul Society.

After affirming alongside his friends that they will emit weak Reiatsu in order to alert the others if they track down a Bount, Ichigo wonders what Rukia will be doing, which leads her to explain that she has to return to her division now that she is back in Soul Society and has delayed it for long enough. With Ichigo accepting this and Rukia telling him to not do anything rash while they both smile, Ririn angrily interjects and vows to find the Bount first so that she does not lose to Rukia before flapping her arms and flying away, leaving Ichigo and Rukia to stare after her in confusion while Kurōdo and Noba attribute this to jealousy on Ririn's part.

While Ichigo expresses exasperation at Ririn's behavior and Rukia questions whom she is jealous of, which Kurōdo tries to deflect, Uryū begins walking away and responds to Ichigo's protests by reminding the group that they do not have time to waste and assuring them that he will be fine on his own. Staring at Uryū alongside Orihime, Ichigo turns to Kurōdo and instructs him to keep Orihime safe as he asks Orihime to not push herself too hard, with both of them responding affirmatively, prior to running off with Sado and Noba while Rukia, Orihime, and Kurōdo run off in the opposite direction into different parts of the forest surrounding the lake.

Aftermath
As Ichigo runs through the Rukongai, Sado and Noba run through the forest, Orihime and Kurōdo run along a grassy plain, and Uryū runs beside the underside of a cliff, Hitsugaya delivers instructions and orders in an intersection of the Rukongai to several of his subordinates, who depart with Shunpo once he finishes. Elsewhere, in one of the slums of the Rukongai, Rukia passes several huddled and destitute villagers while mentally observing that the dirt and depression of the area has not gone away. On a different street, an irritated Ririn rapidly runs along and expresses anger at being angry to begin with, only to stop upon sensing a Bount nearby.

With Ririn turning around and running back in fright, Rukia finds herself engulfed in a dust cloud and begins coughing and shielding her face. Suddenly, Rukia looks up to find Yoshi standing at the other end of the street. Initially surprised to see Rukia again, a maliciously grinning Yoshi greets her and comments on the coincidence of them encountering each other again before summoning her Doll, Nieder, which leaves Rukia glaring at her.