When Sasuke is making the Chidori on the waterfall and Naruto is looking up at him, Naruto's necklace is gone.
It is once again expressed that Naruto wasn't as alone as previously anticipated, as we can see from Naruto's flashback, that he was playing and talking with Shikamaru, Choji, and Kiba, in a Konaha playground, at a much younger age.
Naruto (Using the Nine-Tailed Fox's chakra) Sasuke! I'm not letting Orochimaru take you away, do you understand me?! I'll break every single bone in your body if that's what it takes to stop you! You're not going anywhere!
Naruto: (Thinking) Maybe I was the only one who thought...thought we were friends. (Begins to use the Nine-Tailed Fox's chakra)
Sasuke: (Seeing the chakra) I told you, it's too late, Naruto! (Hits Naruto with his Chidori)
Naruto: (Thinking) If that's the case, then how stupid am I Sasuke? I can't help it but... I don't know why... I don't know why, but... But I just can't bear the thought of seeing you taken away by someone like Orochimaru.
Sasuke: You know what they say, don't you, Naruto? When two shinobi are powerful enough, they are able to read each other's thoughts simply by an exchange of fists, without ever uttering a single word. Get it? You've always been naive, Naruto. Tell me, do you know my thoughts? Can you tell what's on my mind?
Naruto: I'll beat you into oblivion if that's what it takes to bring you back home!
Sasuke: I know I've said this already, but be honest with yourself, you've been waiting for this moment too. Kakashi and Sakura aren't here now. Nobody's going to stop us like the last time.
Naruto: You lousy... (Sees Sasuke get a kunai out of his pack)
Sasuke: This time we settle this once and for all. It will be the end of you!
Kakashi: (Thinking) I was too naive. Those two could end up killing each other.
Naruto: (Thinking) The truth is, you and I are friends.
Naruto: (Thinking) That's it, there's no mistaking it now. You're dead serious about this, aren't you?
Naruto: Sasuke! I will not let Orochimaru have you!
Kakashi: (Thinking about how to make Sakura feel better) Well, considering that she saw them fight, it seems pointless to say "don't worry".
Kakashi: I was a fool, they really were trying to kill each other.
Naruto: Sasuke, I always wanted to talk to you. I knew you were all alone, and I was happy that somebody else was too. But I didn't talk to you. You were perfect at everything, and popular with everybody. So, I wanted to surpass you and made you my rival. I wanted to be just like you, you were my inspiration. That's why...at that time...when you acknowledged me, I was happy. That was the first time you said that to me. Although I would never admit it, that's how you and I became friends.
YTV Airdate: May 2, 2008
In the manga, the flashback of Naruto playing with Choji, Kiba, and Shikamaru is either zoomed so far out or their pictures are silhouetted to the point that it is not too clear who he was playing with.
Original Airdate: April 27, 2005
Original Episode Title: Friends!
Romaji Episode Title: Tomoyo!
Kanji Episode Title: 親友（とも）よ！
The full image of Kyubi is seen behind Naruto when Kyubi gives him power. Not just his head like all of the other time.