The Next Challenge! Naruto vs. The Nine-Tails!!

is episode 245 of the Naruto: Shippūden anime.

Summary
Naruto, B, Yamato, and Motoi go back to the Falls of Truth, where Naruto defeats his dark self by acknowledging how it helped him so far. Motoi leaves to report for Kumogakure, and the other three enter the falls, into a temple, where Naruto is supposed to learn to control the Nine-Tails. After pulling a prank on Yamato, they enter a room that is sealed off, so it contains the Nine-Tails should it break free. Naruto meets the Nine-Tails in his mind, who is surprised not to sense the darkness inside Naruto. B instructs Naruto to open the seal holding the Nine-Tails, who berates him for joining forces with the Eight-Tails' jinchūriki and attacks. B protects Naruto from an initial attack and instructs Naruto how to take the Nine-Tails' chakra. Naruto enters Sage Mode and attacks.

Trivia

 * In this episode, Killer B is briefly shown with a Konohagakure forehead protector.