The Forbidden Research...Nozomi's Hidden Secret!

 is the three hundred twenty-ninth episode of the Bleach anime.

Inaba struggles to recover from Mayuri's attack, while his motives and Nozomi's identity are revealed.

Summary
Mayuri Kurotsuchi removes his bracelet and contact lenses, warning Kageroza Inaba about the dangers of a cornered animal. Inaba asks Mayuri when he switched places with the Reigai. Mayuri reveals that he hid in the Dangai and defeated his own Reigai copy when the Reigai lieutenants entered the Human World.

He claims that he took so long because the people that were supposed to come to Soul Society to take it back did not show up. Inaba laughs off Mayuri's remarks and Mayuri uses his extendable arm to grab his neck and tie him up.

Ichigo Kurosaki awakens in the Urahara Shop, confused about what happened to him. Kisuke comments that he has finally woken up and Nozomi angrily asks about defeating Inaba. Ichigo tells her not to be so hard on him. Remembering the mysterious figure he saw while trapped, he asks Renji if he had rescued him from the Cleaner. Renji tells him that he simply brought him to the store when he found him collapsed in the Dangai, leaving Ichigo wondering who the figure was. Kisuke asks Ichigo if he really was swallowed up by the Kōtotsu.

Inaba manages to free himself from Mayuri's arm, earning praise from Mayuri for his combat ability. Mayuri reveals that he was stalling and Inaba surmises that he was waiting for Ashisogi Jizō's ability to take effect and dismisses the notion. Mayuri replies that his Shikai would normally have immoblized him by now and offers to test it by keeping his eyes closed and allowing Inaba to attack him. Inaba refuses to take the bait, surmising that Mayuri is planning something. However, Mayuri walks up to Inaba and stabs him.

Inaba is confused about how he can move his body, yet was unable to avoid Mayuri's simple attack. The captain reveals that he had laced his Zanpakutō with a drug that inhibits the human thought process and injected it into him with his first attack. Mayuri claims that if he had attacked normally, Inaba's instincts would probably have allowed him to dodge the attack, but he was unable to properly react to the simple trick because he was thinking about how to deal with it. He further states that when the drug fully takes control, Inaba will forget how to use all the knowledge he has accumulated thus far.

Kisuke explains that those who wander from the fixed Dangai are doomed to wander it forever unless the Kōtotsu or Kōryū swallows them and they die. He reveals that there are several ways to escape, but no way to be swallowed by the Kōtotsu and survive. He reveals that he does not know how Ichigo survived, but states that he will investigate it. Kon remarks that it is not helpful. Kisuke reveals that the reason Inaba is so obsessed with the Dangai. Inaba researched the Dangai and for ways to control it so that he could find information concealed within the Dangai.

As Mayuri torments Inaba, Suì-Fēng demands that he hurry up and finish him off. Inaba screams, surprising those present. The Reigai of Isane Kotetsu comes to Inaba's aid, forcing Mayuri back and promising to heal Inaba, who notes that not only did Mayuri out do him, but he stopped his thoughts. Inaba laughs this off, claiming that he will admit his weakness today and only today. The Reigai cautions him not to overexert himself, as his body is clearly weaker.

Inaba slashes the Reigai's back and then kills her, apologising for being weak. Mayuri comments on this, saying that his emotions have gotten the better of him now that he cannot think clearly. Inaba grabs the Mod-Soul pill from the remains of the dead Reigai, surprising Mayuri and the others. Hitsugaya asks if it is a Gikon, but Mayuri reveals that it is a Mod-Soul.

Kisuke tells the group that Inaba's objective in researching the Dangai was to learn more about Mod-Souls. Orihime asks what a Mod Soul is and Rukia explains about the Spearhead project, which aimed to create beings with enchanced battle abilities using soulless dead bodies.

With Inaba seemingly no longer able to talk, Mayuri expresses his disappointment that he cannot ask him why he has Mod-Soul technology. However, Inaba tells him that he is on a different level than them and swallows the Mod-Soul pill. Inaba is ejected from his body and reveals that he was using a Reigai. Mayuri theorizes that he forced the Mod-Soul he swallowed to take the effect of the drug. He forces Mayuri back and the Reigai return to his side.

Uryū asks Kisuke how he knew about the Mod-Soul information hidden in the Dangai. He reveals that when he and Renji rescued Ichigo from the Dangai, he noticed an anomaly with the Reishi surrounding Ichigo. When analyising this, he found data fragments relating to the Mod-Souls. He reveals that Inaba used that data to create Mod-Souls of the captains. Nozomi confirms that Kisuke is correct.

Ukitake and Kyōraku ask Inaba how he learned that there was data on the Mod-Souls in the Dangai and who he really is. Nozomi and Inaba claim that Inaba was the one who developed the Mod-Souls. Mayuri dismisses this as a lie, which Inaba angrily decries. Inaba comments on the amount of research that would have been destroyed when the Spearhead project was abandoned and how advanced it was. His Mod-Souls would have been incubated with a portion of a Shinigami's Reishi, inheriting their mental structure and enhancing their abilities.

Ukitake reveals that the reason Spearhead was scrapped was because the ability to freely control the capabilities of Mod-Souls was deemed a threat. Inaba concurs, saying that he could not forgive their foolishness and converted the information into special Reishi and threw it into the Dangai. Nozomi reveals that he studied the Dangai for a long time and retreived the information that was inside the Kōtotsu. Hearing this, Kon realizes that Nozomi did not trust him because he was a Mod-Soul. Nozomi denies this, saying that Inaba did not create him.

Inaba destroys the braclets of the Reigai, prompting them to release a large volume of reiatsu. He reveals that the Reigai had been holding back their full power and more Reigai appear, including those that had already been defeated. Mayuri explains that as long as their core form, the pill, is preserved, their bodies can be replaced. Inaba tells Mayuri that not even he could create Reigai that could withstand such reiatsu. The Reigai engage in a grand melee with the captains, with the captains being overwhelmed.

Nozomi reveals that she was the very first Mod-Soul to be developed.

Shinigami Illustrated Picture Book
Suì-Fēng explains how Yoruichi rescued her. She was held captive in a castle, wearing a dress and unable to move. Yoruichi appeared at a window in a military uniform and carried her away in her arms. Isane points out that she was there as well, provoking an angry response from Suì-Fēng.

Powers and Techniques Used
Zanpakutō released:

Shikai:
 * Fuji Kujaku (藤孔雀, Wisteria Peacock)
 * Fuji Kujaku (藤孔雀, Wisteria Peacock)
 * Fuji Kujaku (藤孔雀, Wisteria Peacock)
 * Fuji Kujaku (藤孔雀, Wisteria Peacock)
 * Fuji Kujaku (藤孔雀, Wisteria Peacock)
 * Fuji Kujaku (藤孔雀, Wisteria Peacock)

Bankai: