After passing the Bell test, team 7 started doing D rank missions to improve their teamwork. Naruto didn't complain and completed D rank missions easily. He took the rest of the time training. He also visited Karin by using Flying thunder god and helped her in her training when he was free. Karin after all this training, has reached high chunin level and just a step away from reaching special Jonin. They also got their mission of catching the cat Tora and it went without a hitch as Naruto was faster than the CAT even without using the fruit powers.
In the D rank missions, most of the work was done by Naruto. Kakashi also saw this and reported everything to the Hokage. One day, while they completed the mission, the Hokage summoned them urgently. After they arrived at the Hokage's office, Hiruzen spoke "I have a mission for you Kakashi. I had sent Kurenai and her team to an escort mission to the land of waves and got a distress signal from the team. I want you to go and provide support for the team. The destination is the land of waves". Kakashi answered "Yes lord Hokage." Then he told his team to meet him at the gate in an hour. Naruto thought 'This must be fate for team 7 to go to the land of waves'.
Some days back, Hiruzen had handed a mission to Kurenai and her team to escort a bridge builder named Tazuna to the land of waves. It was supposed to be a C rank mission and Was going smoothly until two mist rogue ninjas attacked the team. The rogue ninjas were subdued easily by Kurenai and she enquired Tazuna and he spilled the beans regarding not having enough money to hire a higher ranked mission. Hearing this, Kurenai was thinking of the safety of her team. Tazuna also pleaded her by making her feel guilty, but as she was a Jonin level Ninja, she knew better. So she decided to abandon the mission as it was not her fault that the mission details were wrong.
Her team consisted of Kiba, Hinata and Shino. Kiba was afraid of his life so he didn't speak up anything. Hinata was too shy to speak and shino normally didn't speak much. So the mission got abandoned, but as they were ready to leave, Zabuza attacked them to kill Tazuna. Knowing that they had no choice but to fight, Kurenai started fighting with Zabuza. She soon found out that she was not a match for Zabuza. In the fight, Zabuza hurt Tazuna, but failed to kill him as Hinata, Kiba and shino joined the fight. As the fight went on, Kurenai was badly hurt. But unknown to Zabuza, Shino's insects had eaten away a huge amount of his chakra. Feeling something wrong, he retreated saying "We'll meet next time and I'll finish you off then."
After he left, Kurenai fell on her knees and somehow sent a distress signal back to the village before she fainted. Tazuna then offered them a place to stay in the village as the village was closer than Konoha and as everyone was hurt, they couldn't travel back to Konoha in that condition. They accepted his offer and went to his house. The distress signal soon reached Hiruzen and Hiruzen summoned team 7 as Kakashi was an Elite Jonin and he had confidence in Kakashi to take down any threats that Kurenai might have been facing. Thus he gave the mission to Kakashi and his team.
After an hour, Naruto, Sasuke and Sakura arrived at the village gate. Kakashi also arrived soon. Then all three of them started making their way towards the land of waves. Kakashi warned them "Be careful. There must be other ninjas involved in the mission. That must be the reason for the distress call from Kurenai's team. Be on guard all the time and be ready for an ambush". The three of them nodded and they continued. Soon they reached the land of waves and went into Tazuna's house. There they saw Kurenai and Tazuna with bandages all over and Kurenai explained to them what happened and about Zabuza.
At a cave in the Land of waves, Zabuza was sitting while there were some dead insects in front of him. He said "Haku, it was a good idea to retreat. These insects were consuming my chakra and we would have lost if the fight continued." Haku nodded and spoke "You are right Zabuza. But now, that women might have called for reinforcements." Zabuza also understood this "I know. Now contact them. Even if we have to share the rewards, their help is needed. Konoha must have sent another Jonin. There's no other way. Otherwise we have to abandon this mission." Haku nodded "Yes Zabuza. I'll contact them". Then Haku flickered out of the cave and Zabuza thought 'I want to see who Konoha has sent as backup'.
The next day, Kakashi came to the forest with the team in hopes of training them for the fight. After reaching the forest, he spoke "I'll train you in chakra control. The first is the tree climbing exercise. First concentrate some chakra on your feet and then use the right amount then step on the tree." He climbed the tree as demonstration. Naruto just climbed the tree easily which surprised Sakura and angered Sasuke. Kakashi already had believed that Naruto could do it. Sakura was second as she climbed the tree in just a few tries.
Kakashi then told all three of them to practice and left back to Tazuna's house. Naruto went away deep inside the forest and used Flying thunder god to go to Karin and spend some time with her. Sasuke failed many times and finally asked Sakura for advice. Sakura was happy to help and finally Sasuke managed to do it. He climbed the tree and had a satisfied look on his face. The sun was setting and Naruto also came back. Then all three of them returned back to Tazuna's house for dinner. After dinner, As the house was crowded, Naruto told them that he would sleep outside and went out teleporting himself to Uzumaki village to spend the night there. He didn't care if anyone attacked the team while he was gone.