Zero Visibility: The Sharingan Shatters

is episode 15 of the original Naruto anime.

Synopsis
Kakashi revealed his Sharingan to Zabuza once again. Zabuza tried to prevent it by stabbing Kakashi's hand. Kakashi revealed his Sharingan regardless. Zabuza explained how Haku had observed Kakashi's Sharingan and discovered a way to counter it. Zabuza then proceeded to explain how Haku's jutsu even surpassed his own.

Meanwhile, inside the mirrors, Naruto began to replicate over and over again. After a couple of times, Sasuke began to be able to see Haku's movements. Sasuke kicked water into the air, which he used to detect Haku. He then began to think that perhaps something else would work as well. When Haku began attacking Naruto's clones again, Sasuke sent his Fire Release: Great Fireball Technique into Haku's back, and actually managed to hit Haku slightly. Then, Haku tells him that only a huge amount of fire can melt the ice mirrors. This angers Sasuke and he was ready to try again, but this time Haku attacked Sasuke first.

Zabuza used his Hiding in Mist Technique, but this time the mist was so thick that not even he would be able to see through it. Kakashi deflected a few shuriken, and Zabuza claimed the next time Kakashi would see him would be when Kakashi would die. Zabuza vanished again, and Kakashi tried to think in a similar fashion to Zabuza, trying to figure out where Zabuza would strike. Kakashi finally realized Zabuza would attack Tazuna and Sakura. He quickly rushed to his side and took an attack from Zabuza as Sakura screamed.