Tōshirō Hitsugaya vs. Gin Ichimaru is a fight taking place during the Ryoka Invasion between 10th Division Captain Tōshirō Hitsugaya and 3rd Division Captain Gin Ichimaru, prompted by the actions of 5th Division Lieutenant Momo Hinamori after the apparent murder of her captain, Sōsuke Aizen.
10th Division Lieutenant Rangiku Matsumoto wakes up on a couch in the office of her captain, Tōshirō Hitsugaya, who asks her if she is awake as he sits behind his desk nearby. Upon being asked by Rangiku what he is doing in her room, an irritated Hitsugaya points out that this is the office and not her room before instructing her to take over for him if she is awake. Walking over to Hitsugaya's desk, Rangiku points out that it is his fault for taking on the Fifth Division's work, but is surprised when Hitsugaya hands her only a few sheets of paper and tells her to go to her own desk with them.
Rangiku questions if this is really all that is left since there were multiple stacks of paper when she last checked and notes that she must have slept for a long time while Hitsugaya brushes this off and begins to drink from his cup. As he notices Rangiku's tone, Hitsugaya tells her she does not have to do the paperwork because it must have been hard to see her classmate, 3rd Division Captain Gin Ichimaru, and 5th Division Lieutenant Momo Hinamori like that. After repeating Hitsugaya's description of Gin as her classmate, Rangiku inquires if he really believes Gin killed Hinamori's captain, Sōsuke Aizen.
Suddenly, 10th Division 7th Seat Kōkichirō Takezoe announces his presence from outside the door to the office, and after Hitsugaya confirms that he and Rangiku are present and orders him to come in, a kneeling Kōkichirō slides open the door and apologizes for interrupting before revealing the prison guards have reported that 6th Division Lieutenant Renji Abarai, 3rd Division Lieutenant Izuru Kira, and Hinamori are missing from their cells. Soon afterward, outside the jail cell where Hinamori was being kept, the guard that was on duty bows before Hitsugaya and Rangiku as he recounts how everything went white for him after he turned to face Hinamori.
As he concludes that she was gone when he woke up, the guard declares that this was simply inexcusable, and after he notes that Hinamori must have used Hakufuku, Hitsugaya explains to the confused guard how Hinamori is a master of Kidō whose powers they should have sealed if they were serious about imprisoning her, though they did not do so because no one thought she would go this far. Standing next to the giant hole in the cell bars and wall behind them, Rangiku questions why Hinamori would do this when she was not facing execution, but Hitsugaya asserts that there is only one reason and orders Rangiku to go back without him as he grips the handle of his Zanpakutō and proclaims that he is going to rescue Hinamori. Elsewhere, Hinamori runs along a walkway with Aizen's letter in her hand and mentally admits that she could not believe her eyes when she read it, to the point of not believing the letter itself for a time, but concludes that it is true after all as she thinks of Aizen's killer.
Some time later, Gin strolls along a walkway in the Third Division compound with his lieutenant, Izuru Kira, following him. Suddenly, Hitsugaya appears before them on a platform connected to the walkway and states that he knew he would find them here because only Izuru's cell was opened from the outside as he admonishes Gin for not covering his tracks very well. However, Gin asserts that he did this on purpose so Hitsugaya would know, and as he admits that he is glad to have gotten here before Hinamori did, Hitsugaya grips the handle of his Zanpakutō and declares he is going to kill Gin before she arrives, only to be interrupted when Hinamori lands on the platform.
While Hitsugaya is surprised by her arrival, Hinamori states that she has finally found him and notes that this is where he was as she stands up and begins drawing her Zanpakutō. Warning Hinamori to stay back while he deals with Gin because he is too strong, Hitsugaya is stunned to find Hinamori leveling her Zanpakutō next to his neck as she declares that this is for Aizen while Gin smiles behind her. Hinamori recounts the contents of Aizen's letter: believing that he is most likely dead if this is being read, Aizen entrusted the truth of what he has discovered to the one whom he trusts the most and revealed his investigation led him to conclude the goal of Rukia Kuchiki's execution and its constantly-changing date is not to kill Rukia herself, but instead to steal the Sōkyoku, whose seal is only removed for executions and which has the power of one million Zanpakutō.
Noting that the the execution stand itself has the power to withstand an equal number of Zanpakutō and that the power of the Sōkyoku momentarily increases by several dozen times when executing a Shinigami, Aizen's letter asserts that the one who plotted Rukia's execution intends to destroy the entirety of Soul Society in addition to the Seireitei with the Sōkyoku and that this person is Hitsugaya. As a tearful Hinamori finishes recounting this, Hitsugaya is left stunned by Aizen's letter saying this, and after affirming this, Hinamori elaborates that Aizen also said he called Hitsugaya out to the East Holy Wall that night in an effort to foil his plans.
Hinamori continues that Aizen was prepared to cross blades with Hitsugaya if he did not back down, but requested that Hinamori kill Hitsugaya in his stead if he should be killed. A trembling Hinamori concludes that this was Aizen's last wish, asked of her as a man rather than her captain, and screams as she attacks Hitsugaya, creating a large explosion of force on impact. Sent skidding back by this, Hitsugaya questions if Hinamori is crazy and points out how Aizen was not the type of man to start a fight he could not win or the sort of coward who would make his subordinates clean up his mess. Despite this, Hinamori declares that this is what the letter said and that she did not misread it before slashing at Hitsugaya while clarifying that the letter was written in Aizen's handwriting, further stunning him as he narrowly dodges. Continuing to attack Hitsugaya, Hinamori promises that she did not want to believe this.
Though she claims that she had no choice because it was Aizen's last wish, Hinamori stops attacking and admits that she does not know what to think anymore while openly weeping, to Hitsugaya's astonishment. After leaping into the air to avoid Hinamori's subsequent attack that craters the ground where he was standing, Hitsugaya observes that she is too upset to think straight and concludes that someone must have forged the letter so he and Hinamori would kill each other because Aizen would never write it. Upon looking down to see Gin grinning up at him, Hitsugaya angrily accuses him of engineering this as well and falls toward him while preparing to draw his Zanpakutō, but finds himself confronted by Hinamori in midair. With Hinamori stabbing at him, Hitsugaya realizes that he cannot dodge her in midair and is forced to knock her out with a blow to the head.
As he lands in front of her after she crashes into the platform below, Hitsugaya calls out to Hinamori and is shocked upon seeing her unconscious body. When Gin approaches and admonishes him for hitting Hinamori so hard, Hitsugaya recalls the former's enigmatic exchange with Aizen after the intruder alarm was sounded and inquires what Gin is planning. Hitsugaya asserts that Gin had to make Hinamori suffer because Aizen was not enough for him and points out how Hinamori's hands are bleeding from how hard she was gripping the handle of her Zanpakutō. Though Gin expresses confusion at what he is talking about, Hitsugaya reminds Gin of his promise to kill the latter if he ever made Hinamori bleed and furiously rips his Zanpakutō out of his sheath, prompting Gin to sigh and assert that he will be forced to stop Hitsugaya if he draws his blade here while gripping the handle of his own Zanpakutō.
With Gin and Hitsugaya facing each other while exerting their Reiatsu, Izuru nervously addresses Gin, only for the latter to warn him to stay back if he does not want to die yet. Declaring that this is not good enough, Hitsugaya instructs a stunned Izuru to disappear and keep going even after he can no longer see them because there is no guarantee that Hitsugaya will not end up killing him if he is within three ri of the fight. After leaping into the air above Gin, Hitsugaya releases his Shikai, Hyōrinmaru, adding a long chain to his Zanpakutō's handle and creating a massive dragon out of water and ice that swirls around him as the moon is covered by storm clouds.
Hitsugaya sends the dragon crashing into Gin onto the platform below, causing it to burst into a torrent of water on impact, and as he leaps out of the splash radius while mentally admitting that he could not dodge it in time, Izuru is astonished to find his soaked arm freezing solid. Above, Gin moves to the roof of the nearby building and finds Hitsugaya sending another wave of ice toward him with a slash of Hyōrinmaru and slashes through the wave with his Zanpakutō, only to suddenly find his left arm frozen and bound by the chain on the end of Hyōrinmaru while Hitsugaya stands behind him. Though Hitsugaya declares that it is over, Gin releases his own Shikai, Shinsō, which extends through his haori toward Hitsugaya's eye. With Hitsugaya barely evading in time by falling onto his back, Gin questions if he really wishes to dodge it because Hinamori will die.
Looking behind him, Hitsugaya realizes that Shinsō is hurtling toward Hinamori's unconscious body nearby. Suddenly, Rangiku appears in front of Hinamori and blocks Shinsō with the broad side of her Zanpakutō, shocking those present, before explaining that she came back after heading to the barracks because she sensed the Reiatsu of Hyōrinmaru. Upon being requested by Rangiku to withdraw his sword or deal with her directly, Gin merely smiles as his frozen arm begins to bleed.
Gin retracts Shinsō, leaving Rangiku trembling as she holds her cracked sword. When Gin prepares to leave, Hitsugaya demands that he stop, prompting Gin to assert that Hitsugaya should see to Hinamori rather than chase him before disappearing with Shunpo. Later, Hitsugaya stands with Rangiku in front of Hinamori as she lies unconscious in a bed with medical equipment hooked up to her in their barracks, where he thanks Rangiku for arriving when she did because Hinamori would be dead had she not, though Rangiku downplays this. Reflecting on Gin's sudden departure and lack of explanation, Rangiku notes that Gin's bad habit of leaving without telling her where he is going has not changed from when he was a child and wonders where he is trying to go.
Beside her, Hitsugaya ponders how much of Aizen's letter to Hinamori was fabricated and if the plot to destroy Soul Society with the released power of the Sōkyoku during Rukia's execution is actually Gin's plan. Suddenly, the two of them are approached by a Jigokuchō, which relays the Central 46's decision to make a final change to the date of Rukia's execution by having the sentence carried out twenty-nine hours from now with no further changes, to Hitsugaya and Rangiku's shock. Upon seeing Hitsugaya briskly walking off, Rangiku calls out to him, only to be informed that she and Hitsugaya are going to stop the execution because Gin cannot be allowed to succeed if the execution and the release of the Sōkyoku are part of his plan.