I believe that Sasuke will go over the line in someway, more than likely by either hurting or killing Sakura, thus sending Naruto completely out of control (possibly going Nine-Tails) and murdering Sasuke. Then after Sasuke is dead, Naruto will stil be out of control and have to be contained somehow. Sakura (If she's still alive) will attempt to stop Konoha from killing or sealing Naruto and somehow bring him back to normal. Afterwards, after realizing He has killed Sasuke, he will either leave Konoha or simply walk right into Akatsuki in the hopes of them removing the Kyuubi.