The Top-Secret Mission…!! (volume)

Synopsis
Kabuto, having always been loyal to Orochimaru, turns against Yamato, forcing him to call in Naruto, Sakura, and Sai for help. Naruto is drawn into battle with Orochimaru, and all the while his rage grows, allowing the demon fox within him to turn Naruto into a four-tailed manifestation of itself. This new Naruto attacks Orochimaru, who is only barely able to repel him. To stop Naruto from continuing his attack, Yamato uses his unique abilities to suppress the demon fox's influence, returning Naruto to his normal state. Meanwhile, Sai joins sides with Orochimaru on behalf of his organization, Root, and they take him back to their hideout. Once learning of this Yamato, Naruto, and Sakura follow him, hoping that he can lead them to Sasuke.