"Infiltration…!!" (潜入…!!, Sennyū…!!) is chapter 302 of the original Naruto manga.
Kabuto escorts Sai to a room and locks him in to prevent him from exploring. Sai takes the time alone to as a chance to look at the orders given to him by Danzō. Meanwhile, Team 7 infiltrates the base and locates Sai in his room. Sakura returns his picture book and they ask him about his reasons for joining up with Orochimaru. He confesses that he is helping Danzō and Orochimaru plan another invasion of Konoha.