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

Summary
Naruto, Killer B, Yamato, and Motoi head to the Falls of Truth, where Naruto decides to undergo the first test again. Once more, he encounters his dark self, but instead of attacking him, he thanks him for all the times his anger has helped him and hugs him. With his anger quelled, the darkness in Naruto's heart vanishes and he passes the first step.

As Motoi excuses himself to report back to Kumogakure, the other three head to the Tailed Beast Temple hidden behind the waterfall, where countless jinchūriki have come to hone their control over their tailed beast. The process involves Naruto communicating directly with the Nine-Tails in a special chamber in an attempt to gain control over its power; however, should he fail, the Nine-Tails would go on a rampage, at which point it would be immediately sealed within the room, albeit at the expense of Naruto's life. Killer B asks what type of seal Naruto has, and is impressed that he possesses the Four Symbols Seal, claiming it to be more effective than his Iron Armour Seal. Naruto then attempts to mentally communicate with his tailed beast, with Killer B linking his mind with Naruto's to guide him along the way.

Naruto comes face-to-face with the Nine-Tails once more, who is surprised since he is unable to sense Naruto's hatred, which is usually what causes the two of them to have an encounter. Using the key he was given by Gerotora, Naruto completely undoes his seal, setting the fox free. However, Killer B reminds him that if Naruto does not subdue the fox, the fox would take over and he would die. Killer B uses his chakra to manifest octopus legs to bind the Nine-Tails. Realising that Naruto is attempting to control him and infuriated that he is getting help from the Eight-Tails, he breaks out of his binds and launches a Tailed Beast Ball at Naruto. Since Naruto's real body is not moving, Naruto is able to amass natural energy and enter into Sage Mode, and proceeds to hit the Nine-Tails with his senjutsu-enhanced Ultra-Big Ball Rasengan.

Trivia

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