The Truth about the Nine-Tails!! (九尾の真実!!, Kyūbi no Shinjitsu!!) is chapter 490 of the Naruto manga.
In exchange for joining forces, Kabuto requests that Tobi give him Sasuke. He reincarnates someone to force Tobi to agree. Tobi tells Kabuto that he can have Sasuke once the war is over. They make plans for the battles ahead. Anko, having been led there by a trail of bodies left by Kabuto, relays Tobi's location to Konoha. At Mount Myōboku, Naruto considers what to do with the key to the Nine-Tails' seal. Although Jiraiya wanted him to use it to gain control of the fox's power, it is easier said than done. Knowing he will need its power if he is to defeat Sasuke, Naruto accepts that he cannot put it off any longer.