Land Ahoy! Is this the Island of Paradise?

is episode 243 of the Naruto: Shippūden anime.

Summary
While still at sea, the ship is attacked by the Giant Squid whom the ship's captain had tried to warn them about. They are however saved by Killer B. As Naruto and his Konoha bodyguards disembark on the Land of Lightning Island, Naruto approaches B and asks for his help in learning to control a tailed beast. B initially appears uninterested, so Naruto tries to sell him on the idea by acting like him. In doing so he accidentally insults B, so B refuses. Naruto asks Motoi, the island's caretaker, how he can convince B, claiming that B is too conceited. Motoi grows angry by Naruto's accusations, but lets it go. He tells Naruto that B probably had his reasons and directs him to the Falls of Truth. He tells Naruto that it is the place that B was trained to control the Eight-Tails. He then tells Naruto to enter the falls to face his inner self. A "dark Naruto" confronts him, calling him an imposter. B is shown fighting in a competition with several bears where he easily defeats Kintoki telling him that he'd got soft. The Eight-Tails then asks B why didn't he help Naruto if he had time to play with bears telling him that even though he didn't like the Nine-Tails, Naruto showed promise and that that Naruto reminded him of himself and B. Dark Naruto asks why he didn't humour the earlier, "shallow" Konoha villagers with autographs. As Naruto tries to defeat his "inner darkness", the product of his lonely childhood and the lone obstacle in his efforts to tame the Nine-Tails. They are equally matched, so the fight does not go anywhere. Since this is an internal struggle, Naruto returns his attention to the real world and tells them what had happened much to Yamato's shock. Motoi however, implores Naruto to defeat the doppelgänger, otherwise he would not be able to continue his quest to control the Nine-Tails.