"A Dangerous Mission! Journey to the Land of Waves!" (重要任務!波の国へ超出発!, Jūyō Ninmu! Nami no Kuni e Chō-shuppatsu!) is episode 6 of the original Naruto anime.
After Team 7 successfully finds Tora, the lost cat of the Fire Daimyō's wife, they return it back to her. With their mission successfully completed, the ThirdHokage informs them of the available D-rank missions, such as babysitting the chief counsellor's three year old. Naruto expresses that he wants to go on a real mission that's exciting and challenging. Iruka lectures him, stating that like every beginner genin with no experience, he must start with simpler missions to develop his skills. The Third goes on to explain that with a higher ranked mission comes higher difficulty and greater risk to the shinobi. However, Naruto exclaims that he is a ninja now and wants to be treated as such. Amused at his statement, the Third decides to give the team a C-rank mission to escort Tazuna, a master bridge builder, to the Land of Waves. When Tazuna meets the team, he expresses disbelief in the fact that kids are going to be guarding him, but works with them nonetheless.
As they make their way to the Land of Waves, twochūnin-level Kiri-nin emerge from a puddle and binds Kakashi with shuriken-laced chains, before pulling and ripping him apart. With Kakashi "defeated", the duo turn their attention to Naruto, who freezes up. Before they can land an attack, Sasuke intervenes and saves Naruto. The duo split up, leaving one behind as the other charges at Tazuna. Sakura steps in front of Tazuna to defend him, before Sasuke appears in front of her to aid. Before anything further can happen, Kakashi appears and effortlessly defeats the duo, though Naruto does attain a small scratch from one of their Metal Gauntlets, which contained poison. It is revealed that Kakashi used the Substitute Technique to escape the duo's initial attack, suspecting an ambush when he discovered their puddle on a clear day. Kakashi compliments Sasuke and Sakura for their courage, but expresses disappointment in Naruto with how poorly he handled the situation. Tazuna questions why Kakashi took so long to help, with the latter explaining that he could have defeated them quickly but needed to know who their target was. Kakashi points out that their target was Tazuna and that had he told them that he would be hunted by ninja, the mission would be a B-rank or higher, and a different team would have been assigned. Sakura suggest they quit the mission, not only due to the higher difficulty, but because of Naruto's wound. Unwilling to jeopardise the mission, Naruto decides to take out a kunai and uses it to remove the poison from his hand. He then makes an oath that he will never run away or back down from any mission, threat, or enemy, as well as not lose to Sasuke. After this, Kakashi bandages Naruto's wound so he doesn't bleed out, but discovers that it had already begun to heal due to the Nine-Tailed Demon Fox.
Elsewhere, Gatō, the man who hired the Demon Brothers to eliminate Tazuna, complains about their failure to Zabuza, the duo's apparent boss. Zabuza raises his Kubikiribōchō at Gatō to shut him up, and states that he will handle it himself. Gatō informs him that they will be expecting another assault and that a high-level ninja is accompanying Tazuna. This doesn't faze Zabuza, who just replies that he is the "Demon of the Hidden Mist".