"Nine-Tails…!!" (九尾…!!, Kyūbi…!!) is chapter 28 of the original Naruto manga.
In his anger, Naruto unknowingly taps into the chakra reserves of the Nine-Tailed Demon Fox. Kakashi senses this and, worried that the seal that keeps the fox sealed within Naruto has been broken, decides it is time to finish his battle with Zabuza. When he sees that Naruto's mysterious chakra source also heals all the damage he has sustained, Haku tries to flee. In one quick motion, Naruto avoids one of Haku's attacks and catches Haku. He then punches Haku in the face, sending him flying and shattering his ice prison. Naruto charges to deliver the finishing blow, and Haku turns to face his death, revealing that the mask he has been wearing in the entire battle has been broken.