The Betrayal's Conclusion!! (裏切りの結末!!, Uragiri no Ketsumatsu!!) is chapter 290 of the Naruto manga.
Kabuto begins asking about information that only the real Sasori would know, so Yamato prepares to capture him. At the same moment Orochimaru confronts them. Having been alerted by Yamato's action, Kabuto is able to get away and join up with him. Yamato starts to wonder how he will fight Orochimaru while maintaining his disguise as Sasori when Kabuto cuts off the disguise's head. Yamato flees and Orochimaru points out that he is not Sasori, Kabuto not knowing what the real Sasori looks like. Outnumbered, Yamato calls in Naruto, Sakura, and Sai.