Zero Hour! The Konoha Crush Begins!

is episode 68 of the original Naruto anime.

Synopsis
With the invasion's start, Orochimaru takes the Third Hokage hostage as the Sound Four creates a barrier to allow them to fight without interruption. One of the ANBU chasing after them touches the barrier and dies. Meanwhile, Sunagakure shinobi summon the snake and it breaks through the wall. Then invading Otogakure and Suna ninja infiltrate Konoha, and battles begin breaking out across the village. Kankurō and Temari carry Gaara from the village so that he can recover. Sasuke pursues them, eager to finish their battle. Preoccupied with fending off the invading forces, Kakashi instructs Sakura, who had managed to repel the sleeping-inducing genjutsu, to wake Naruto and Shikamaru. He tells her that they are getting a mission after a long time and includes that they will be getting a fourth member on the team. Sakura wonders who this member is, as Kakashi performs the Summoning Technique hand seals. A cloud of smoke appears and then a dog named Pakkun pops out. Sakura is shocked to see that their fourth member is a dog but Kakashi says that he can track down Sasuke. Meanwhile Might Guy, Aoba and another jōnin battle the incoming Oto ninja. Sakura ducks and proceeds to release the genjutsu on Naruto and Shikamaru.